The CABERNET REFERENCE DHT Preamplifier is the new top of the line, and highest quality preamp ever built by Supratek.
It surpasses the 101D, 300B and 801A preamps in every way and represents a new standard in DHT preamp design.
Incredibly versatile, in addition to the optimally loaded 4P1L DHT gain stage it also has a switchable Lundahl input transformer , a switchable 6SN7 driver stage and a switchable Magnequest output transformer.
All of these options can be used singly or in combination to give a variety of gain, input/output impedances and sonic signatures.
If you want low gain/low output impedance preamp to use with high sensitivity or difficult amplifiers use the 4P1L stage with output transformer switched in.
If you want the highest gain possible (and the resultant dynamics that comes with high gain) switch the input transformer in, the 6SN7 driver stage in and the output stage off.
With three stages, and with such versatility, you are sure to find a combination that is just right for your system.
The heart of the preamp is the 4P1L DHT line stage . Optimally loaded with a v-fet/j-fet CCS and using filament bias it is supremely balanced and open sounding.
Deep strong bass, liquid midrange and shimmering treble it is the ultimate refinement of DHT sound.
Sophisticated design , using the famous Supratek tube shunt regulation and wonderfully complimented by the choice of high quality input and output transformers, which you may switch in or out to further refine the sound to your requirements.
The Lundahl input transformer suits all sources up to 1000 ohms (virtually all digital sources) and is wonderfully clean and transparent - it gives real "oomph" to the 4P1L line stage.
The 6SN7 tube driver stage is suitable for sources up to 100Kohms, tube phono stages etc, and adds a touch of tube euphonics and warmth to the sound, although it is most definitely a state of the art design that is very hi-tech.
The Magnequest output transformer is ideal when a low output impedance is required, it drops the output impedance of the 4P1L from around 1000 ohms ( which is already low enough to drive virtually anything) to around 250 ohms, for the most difficult amplifiers.
It also imparts a slightly different sonic signature that you may enjoy to have at the convenience of a switch.
This is a DHT preamp that does not limit you to the restrictions of a fixed and rigid sonic signature. You will enjoy learning how to get the sound you prefer , and having the ability to enjoy something a little different when the mood or source requires it.
Once again, being a Supratek it is at the forefront of audio design , and incredible value for money, easily besting designs costing 3, 5 and even 10 times the price.
Images soon.
Thursday, May 8, 2014
Tuesday, March 25, 2014
Finally - Beautiful Digital Sound
I've been a champion of Computer Audio for quite a few years now, a little strange for someone who has built around 500 tube phono preamplifiers, and who still insists that a system without a tube preamp, preferably a DHT tube, is missing something.
I believe computer audio (CA) digital passed vinyl in terms of sound quality some years ago. Without the coloration of vinyl the accuracy and resolution of CA reveals exactly what is on the recording, and if it is a very well made recording, it simply gets more of the recording quality passed through . The atmosphere, the ambience ; good CA and good recordings let you hear this, especially in a good system that can do 3D imaging well (think DHT preamp).
Sure vinyl can sound excellent, but take a really good vinyl recording, say something recorded in the 60's , get hold of the master tapes, copy them in hi-rez digital and play back through a high quality CA system and you will be amazed at the fidelity.
BUT. There is still something to be said for vinyl/analog. Yes the CA will have better resolution, be way more accurate, closer to the recording, but the vinyl, despite its coloration and noise has a sense of realism, and "tone" that can be very nice sounding- the terms beautiful and beguiling are often used.
The audiophile world often gets divided into two camps- those that insist in truth and those that insist in tone. Accuracy versus musicality. Digital versus analog.
I dont think it is as clear cut as that, but sure, listening to really good digital is like listening to the recording. Listening to really good vinyl is like listening to a really nice, interesting INTERPRETATION of the recording.
And it sure can sound nice, however I'm the sort of guy that generally prefers things as they really are. I like to listen to vinyl, but its a retro thing, something for fun.
A few months ago, a CA program called AudiophileOptimizer was getting rave reviews from the CA guys, just about without fail, anyone who used it was convinced it was a significant increase in sound quality.
The AudiophileOptimizer (AO) basically optimises a computer so it becomes a digital audio transport only, it shuts down unused computing systems and maximises the audio quality.
Nothing new about that , other products do the same thing , with varying degrees of success. JPlay is another similar program, quite contentious with many claiming it did nothing for the sound, and the media player program JRiver even belittling it publicly.
Others loved it and claimed it was very good.
I tried JPlay and thought that it did provide a slight increase in sound quality, but the cost of using it- a level of bugginess that drove me crazy, was too high for me.
AudiophileOptimizer brought a new game to town. Although it is usually used with a single computer , it can also be used in a dual computer setup. One computer is the "control" - it handles the music files, and the playback process . A media program like JRiver selects the music and can be controlled remotely using iPad or phone or whatever you like.
The "control" computer is connected to a second "audio" computer , preferably by ethernet cable, although wireless can be used.
The "audio" computer uses a different operating system. Instead of Windows 7 or 8 it uses a windows operating system named Windows Server 2012.
Its more basic than 7 or 8 and is designed for specific applications, and it turns out that used as a platform for audio it is much better than the more general use Windows 7 or 8 and Mac OS.
The AO program further refines the operating system for audio use , optimising it to levels of your choice, through the use of different modes.
Highest sound quality is claimed to come from core mode , where the audio computer is completely shut down to all uses apart from passing the audio stream to a dac. Blank screen and controlled by DOS manual input.
Other modes are GUI mode ,which gives a screen and normal computer mouse operation.
The remaining mode is minimal server which is a cross between core and GUI.
Core and minimal-server require a fair bit of computer knowledge and being able to work in DOS language- with the help of a IT guy I was able to try all 3 options and was relieved to hear that GUI mode was my preferred sound. DOS is tricky, CA is hard enough without having to go there.
The dual computer system requires JPlay to be installed on both computers, not so much as for sound quality issues, but as a means of transferring the audio from one computer to another with lowest latency (I think) .
There is a lot of networking to be done. Its not simple and its not a job for the average computer user. I believe the AO program used in a single computer is much simpler, but you still need to know how to install Windows Server 2012 and set it up.
I was grateful to have help from an audiophile IT guy and would have been lost without him (Thanks Tuyen)
So instead of a single computer running Windows 7 and outputting via USB into a dac we have two computers, the control used for selecting the music files and connected to the audio computer which outputs pure audio via USB to a dac.
Seems like a lot of trouble, is it worthwhile?
This what AO claims for sound quality on the website:
- Analog sound quality rarely heard before on computer audio systems
- Bigger soundstage, holographic imaging, more 3D-effect
- Very well defined bass, deeper and more powerful
- Lifelike, fluid and very precise sound reproduction
- Natural air, timbre and image density
- Ability to fine-tune the final sound presentation (through Sound
Signatures and Digital-Filter modes) to achieve outstanding balance
- Sound Signatures and Digital-Filter modes are 100% bit perfect
- Minimizes harshness in digital sound
- Very low noise floor / blacker backgrounds
And its true! Very rarely do claims as strong as this live up to the hype, but the moment I first heard the dual pc set up I was bowled over by the immediate and pronounced lack of "digital" sound. It sounded like vinyl, but even better. Amazing resolution, but sweet, a naturalness that made listening a pure pleasure. Now I had all the accuracy and resolution of a hi rez recording but the inviting, pleasurable experience of vinyl sound.
I've been listening to the dual pc for a while now and still amazed at the new experience of listening to my digital music collection as if for the first time. 16 bit, 24 bit, 44.1, Hi-rez , DSD , even mp3's sound significantly better
And there is the possibility of even better sound- there are a great number of fine-tunings possible with the dual pc system, the AO has Sound and Digital filter choices I haven't investigated yet, and JPlay also has quite a few adjustments to try.
I was so impressed I convinced others to try it.
They heard the results immediately and commented:
This is without doubt the best digital transport available - I haven't heard the ridiculous priced digital ststems, the DCS etc, but I doubt they can compete with the sound of the dual pc, Audiophile Optimized Windows Server 2012 system.
It is incredible sounding, the biggest advance in digital I've heard. At last we can hear what digital really sounds like, and it is beautiful. And at the progress digital is making, hang on to your seat!
The unfortunate thing is that the installation and maybe even the operation of a dual pc is beyond the ability of the average audiophile- you need a certain amount of computer skill or at least the help of someone who understands networking and OS installation.
I'm confident that, because the result is so profound, someone will bring out a music server that contains two operating systems in the one box and will be ready to go very soon.
My control pc is an ordinary late model Toshiba laptop, its used mostly for audio, but is also used for downloading music etc.
The audio PC is a bit special, its a fanless high speed, high power super-duper computer that was especially built for me as an audio only PC. But it only really came to life with Windows Server 2012 and AO.
There is some retro in this system, although I have very good 32 bit/384Khz dacs , with the dual pc I just love the sound of my "old" TDA1541 dac, although it has been modified for USB-I2S input and has the formidable AD844 I/V output.
Control screen
Audio screen
http://www.highend-audiopc.com/optimizer.html
( not involved in any way with highend-audiopc)
While I'm here I'd like to also tell you about my other digital system, which uses Amarra Symphony media player program, incorporating Dirac's IRC room/speaker correction system.
The Windows Server/AO system referred to above is used with a set of active monitor speakers, they are quite accurate and they couple well with the room, I found no real need for room or speaker correction with them, and they sound so good with the AO system that I'm loathe to change anything.
However my hybrid Martin Logan electrostatics are a different kettle of fish. They have had the passive crossovers removed (passive crossovers are very dynamic limiting) and are connected from a DHT tube pre to a DEQX digital active crossover, and then into a high power Carver Sunfire 5 channel power amp. 2 channels for bass drivers, 2 for the stat panels.
Because the passive crossovers are gone there is no level adjustment for the bass driver/ stat panel combination, and as the bass drivers are higher efficiency they sound louder than the stats , giving an unequal bass heavy response. The obvious way to balance this is with DEQX's active crossover level adjustment.
And indeed doing this and using some DEQX equalisation very good sound can be produced. With the passive crossovers gone Martin Logans can be VERY dynamic, they can play very loud and very clean, great for recreating a live performance, with the electrostatic capabilities of detail and slam.
Electrostatics are quirky by nature and getting them to couple with a room well can be challenging. Stats really lend themselves to room/speaker correction. But the results are not always convincing and often the price to pay is too much to bear , with indifferent results.
The Ammara IRC room correction is one of the latest DSP room correction products and it is very good. Not only does it do frequency correction, it is phase linear and gives near perfect impulse response. Its a big step up from outdated digital correction.
I left the levels of bass and stat drivers unchanged and measured the combination of room and speaker.
On the image below the white lines are the measured response of left and right channels.
It looks a bit wobbly but this total response of speakers and room isn't actually too bad,
I believe computer audio (CA) digital passed vinyl in terms of sound quality some years ago. Without the coloration of vinyl the accuracy and resolution of CA reveals exactly what is on the recording, and if it is a very well made recording, it simply gets more of the recording quality passed through . The atmosphere, the ambience ; good CA and good recordings let you hear this, especially in a good system that can do 3D imaging well (think DHT preamp).
Sure vinyl can sound excellent, but take a really good vinyl recording, say something recorded in the 60's , get hold of the master tapes, copy them in hi-rez digital and play back through a high quality CA system and you will be amazed at the fidelity.
BUT. There is still something to be said for vinyl/analog. Yes the CA will have better resolution, be way more accurate, closer to the recording, but the vinyl, despite its coloration and noise has a sense of realism, and "tone" that can be very nice sounding- the terms beautiful and beguiling are often used.
The audiophile world often gets divided into two camps- those that insist in truth and those that insist in tone. Accuracy versus musicality. Digital versus analog.
I dont think it is as clear cut as that, but sure, listening to really good digital is like listening to the recording. Listening to really good vinyl is like listening to a really nice, interesting INTERPRETATION of the recording.
And it sure can sound nice, however I'm the sort of guy that generally prefers things as they really are. I like to listen to vinyl, but its a retro thing, something for fun.
A few months ago, a CA program called AudiophileOptimizer was getting rave reviews from the CA guys, just about without fail, anyone who used it was convinced it was a significant increase in sound quality.
The AudiophileOptimizer (AO) basically optimises a computer so it becomes a digital audio transport only, it shuts down unused computing systems and maximises the audio quality.
Nothing new about that , other products do the same thing , with varying degrees of success. JPlay is another similar program, quite contentious with many claiming it did nothing for the sound, and the media player program JRiver even belittling it publicly.
Others loved it and claimed it was very good.
I tried JPlay and thought that it did provide a slight increase in sound quality, but the cost of using it- a level of bugginess that drove me crazy, was too high for me.
AudiophileOptimizer brought a new game to town. Although it is usually used with a single computer , it can also be used in a dual computer setup. One computer is the "control" - it handles the music files, and the playback process . A media program like JRiver selects the music and can be controlled remotely using iPad or phone or whatever you like.
The "control" computer is connected to a second "audio" computer , preferably by ethernet cable, although wireless can be used.
The "audio" computer uses a different operating system. Instead of Windows 7 or 8 it uses a windows operating system named Windows Server 2012.
Its more basic than 7 or 8 and is designed for specific applications, and it turns out that used as a platform for audio it is much better than the more general use Windows 7 or 8 and Mac OS.
The AO program further refines the operating system for audio use , optimising it to levels of your choice, through the use of different modes.
Highest sound quality is claimed to come from core mode , where the audio computer is completely shut down to all uses apart from passing the audio stream to a dac. Blank screen and controlled by DOS manual input.
Other modes are GUI mode ,which gives a screen and normal computer mouse operation.
The remaining mode is minimal server which is a cross between core and GUI.
Core and minimal-server require a fair bit of computer knowledge and being able to work in DOS language- with the help of a IT guy I was able to try all 3 options and was relieved to hear that GUI mode was my preferred sound. DOS is tricky, CA is hard enough without having to go there.
The dual computer system requires JPlay to be installed on both computers, not so much as for sound quality issues, but as a means of transferring the audio from one computer to another with lowest latency (I think) .
There is a lot of networking to be done. Its not simple and its not a job for the average computer user. I believe the AO program used in a single computer is much simpler, but you still need to know how to install Windows Server 2012 and set it up.
I was grateful to have help from an audiophile IT guy and would have been lost without him (Thanks Tuyen)
So instead of a single computer running Windows 7 and outputting via USB into a dac we have two computers, the control used for selecting the music files and connected to the audio computer which outputs pure audio via USB to a dac.
Seems like a lot of trouble, is it worthwhile?
This what AO claims for sound quality on the website:
- Analog sound quality rarely heard before on computer audio systems
- Bigger soundstage, holographic imaging, more 3D-effect
- Very well defined bass, deeper and more powerful
- Lifelike, fluid and very precise sound reproduction
- Natural air, timbre and image density
- Ability to fine-tune the final sound presentation (through Sound
Signatures and Digital-Filter modes) to achieve outstanding balance
- Sound Signatures and Digital-Filter modes are 100% bit perfect
- Minimizes harshness in digital sound
- Very low noise floor / blacker backgrounds
And its true! Very rarely do claims as strong as this live up to the hype, but the moment I first heard the dual pc set up I was bowled over by the immediate and pronounced lack of "digital" sound. It sounded like vinyl, but even better. Amazing resolution, but sweet, a naturalness that made listening a pure pleasure. Now I had all the accuracy and resolution of a hi rez recording but the inviting, pleasurable experience of vinyl sound.
I've been listening to the dual pc for a while now and still amazed at the new experience of listening to my digital music collection as if for the first time. 16 bit, 24 bit, 44.1, Hi-rez , DSD , even mp3's sound significantly better
And there is the possibility of even better sound- there are a great number of fine-tunings possible with the dual pc system, the AO has Sound and Digital filter choices I haven't investigated yet, and JPlay also has quite a few adjustments to try.
I was so impressed I convinced others to try it.
They heard the results immediately and commented:
"I took your advice and created a separate partition on my Toshiba laptop and installed Server 2012 with AudioOptimizer. Even though I have only the simple SinglePC setup running the Server 2012 GUI Edition, I heard the difference immediately. You're right, it is excellent and sounds just like analog, without the ticks and pops. My guess is that it reduces and/or changes the nature of the jitter.
Now I need to get a second laptop so I can upgrade to the DualPC setup running in Core mode."
"Last night brought over my windows 7 jriver laptop to compare against my friend's dual pc jplay/jriver windows server 2012 core mode setup (similar to yours. but he hasn't got AO though). Improvements with the later setup was quite pronounced. More coherent, organic, natural, dynamic and less 'noise'."
This is without doubt the best digital transport available - I haven't heard the ridiculous priced digital ststems, the DCS etc, but I doubt they can compete with the sound of the dual pc, Audiophile Optimized Windows Server 2012 system.
It is incredible sounding, the biggest advance in digital I've heard. At last we can hear what digital really sounds like, and it is beautiful. And at the progress digital is making, hang on to your seat!
The unfortunate thing is that the installation and maybe even the operation of a dual pc is beyond the ability of the average audiophile- you need a certain amount of computer skill or at least the help of someone who understands networking and OS installation.
I'm confident that, because the result is so profound, someone will bring out a music server that contains two operating systems in the one box and will be ready to go very soon.
My control pc is an ordinary late model Toshiba laptop, its used mostly for audio, but is also used for downloading music etc.
The audio PC is a bit special, its a fanless high speed, high power super-duper computer that was especially built for me as an audio only PC. But it only really came to life with Windows Server 2012 and AO.
There is some retro in this system, although I have very good 32 bit/384Khz dacs , with the dual pc I just love the sound of my "old" TDA1541 dac, although it has been modified for USB-I2S input and has the formidable AD844 I/V output.
http://www.highend-audiopc.com/optimizer.html
( not involved in any way with highend-audiopc)
AMARRA Symphony with IRC
While I'm here I'd like to also tell you about my other digital system, which uses Amarra Symphony media player program, incorporating Dirac's IRC room/speaker correction system.
The Windows Server/AO system referred to above is used with a set of active monitor speakers, they are quite accurate and they couple well with the room, I found no real need for room or speaker correction with them, and they sound so good with the AO system that I'm loathe to change anything.
However my hybrid Martin Logan electrostatics are a different kettle of fish. They have had the passive crossovers removed (passive crossovers are very dynamic limiting) and are connected from a DHT tube pre to a DEQX digital active crossover, and then into a high power Carver Sunfire 5 channel power amp. 2 channels for bass drivers, 2 for the stat panels.
Because the passive crossovers are gone there is no level adjustment for the bass driver/ stat panel combination, and as the bass drivers are higher efficiency they sound louder than the stats , giving an unequal bass heavy response. The obvious way to balance this is with DEQX's active crossover level adjustment.
And indeed doing this and using some DEQX equalisation very good sound can be produced. With the passive crossovers gone Martin Logans can be VERY dynamic, they can play very loud and very clean, great for recreating a live performance, with the electrostatic capabilities of detail and slam.
Electrostatics are quirky by nature and getting them to couple with a room well can be challenging. Stats really lend themselves to room/speaker correction. But the results are not always convincing and often the price to pay is too much to bear , with indifferent results.
The Ammara IRC room correction is one of the latest DSP room correction products and it is very good. Not only does it do frequency correction, it is phase linear and gives near perfect impulse response. Its a big step up from outdated digital correction.
I left the levels of bass and stat drivers unchanged and measured the combination of room and speaker.
On the image below the white lines are the measured response of left and right channels.
It looks a bit wobbly but this total response of speakers and room isn't actually too bad,
although it couldn't be called accurate.
The orange line is the target, what we want the speaker and room to sound like. Its not flat, with a falling response, but this is what gives the most realistic sound in this room, with this speaker.
Below 30Hz has been excluded as I use a separate sub-woofer with DSP EQ to control sub-bass room modes.
The difference in sound with target on and off is remarkable, not only is the frequency response much improved , but the imaging, sound-staging is also much better, no doubt due to the improved impulse response which is a result of the IRC's very sophisticated filters.
Again, its just closer to realism.
This system doesn't have the breathtaking resolution and fidelity of the Windows Server 2012/ Audiophile Optimizer but it has an immediacy and dynamic integration that is exciting to listen to. It really brings the best out of "difficult" and quirky speakers and lets them give of their best.
I have some horn speakers coming soon, and expect Amarra's IRC to work very well with them.
The orange line is the target, what we want the speaker and room to sound like. Its not flat, with a falling response, but this is what gives the most realistic sound in this room, with this speaker.
Below 30Hz has been excluded as I use a separate sub-woofer with DSP EQ to control sub-bass room modes.
The difference in sound with target on and off is remarkable, not only is the frequency response much improved , but the imaging, sound-staging is also much better, no doubt due to the improved impulse response which is a result of the IRC's very sophisticated filters.
Again, its just closer to realism.
This system doesn't have the breathtaking resolution and fidelity of the Windows Server 2012/ Audiophile Optimizer but it has an immediacy and dynamic integration that is exciting to listen to. It really brings the best out of "difficult" and quirky speakers and lets them give of their best.
I have some horn speakers coming soon, and expect Amarra's IRC to work very well with them.
Tuesday, February 4, 2014
Supratek 2014
2014 will be the 27th year of Supratek , this year I'm changing direction a little and only building a limited number of DHT (directly heated triode) preamps.
I've been building DHT preamps longer than any other audio business- I built the worlds first commercially available 300B preamp, also was the first to release a 101D preamp, and as far as I know the first to release a commercial 4P1L based preamp.
I also built over a thousand 6SN7 based indirectly heated triode preamps, the older Syrah, Chardonnay, Sauvignon, Chenin and Cortese preamps are still going strong and most remain with the original owners, a sure sign of customer satisfaction, and reliabilty.
My true love has always been the DHT preamps, there is something about a DHT preamp that is magical, there is no other component that can take you further into the music than a good DHT preamp.
Even today , with digital taking more and more of analog's place in our systems, a DHT preamp always imparts a sense of "rightness" and musical bliss to any system.
There are good technical reasons for this, tubes are linear devices that require no feedback for distortion free playback, and my chosen DHT tubes have the lowest distortion spectrum of audio tubes.
I've become very involved in digital playback the last 3-4 years, it is the future of audio, and DSP (digital sound processing) will enable your stereo system to get closer to the sound of real music in your home.
I have an enormous amount of respect for today's digital designers, they are taking us closer to the sound of the recording than we have ever been.
I never thought I would say this, but I expect to be listening to vinyl digitally soon- I'm presently working on a tube phono/analog to digital convertor.
Why?
In order to take advantage of DSP's amazing capabilities to perfect the speaker/room interface. Done properly (and it's not easy) this can bring vastly superior performance to the very best system.
So does the ancient tube (or valve) still have a place in this new world?
Most definitely. There is still a place for the highly evolved and ultra performance tube preamp. A modern DHT preamp has something that is very hard to describe, it brings an extra sense of realism, enhances the ambience, throws a wider, deeper soundstage and gives pin point imaging .
It's all about impedance conversion and phase performance, and its easy to confirm.
Just take the DHT tube preamp out of a digital system, and you will be connecting it back up again as fast as you can!
And for those still happy with the analog world and not using digital?
The famous Supratek phono preamps now come with DHT line stages.
I'm only making very limited amounts of preamps now, and DHT linestages are what I do best.
This year I will be building a range of DHT preamps using various selected NOS tubes -
please visit my web site www.supratek.biz for details.
I've been building DHT preamps longer than any other audio business- I built the worlds first commercially available 300B preamp, also was the first to release a 101D preamp, and as far as I know the first to release a commercial 4P1L based preamp.
I also built over a thousand 6SN7 based indirectly heated triode preamps, the older Syrah, Chardonnay, Sauvignon, Chenin and Cortese preamps are still going strong and most remain with the original owners, a sure sign of customer satisfaction, and reliabilty.
My true love has always been the DHT preamps, there is something about a DHT preamp that is magical, there is no other component that can take you further into the music than a good DHT preamp.
Even today , with digital taking more and more of analog's place in our systems, a DHT preamp always imparts a sense of "rightness" and musical bliss to any system.
There are good technical reasons for this, tubes are linear devices that require no feedback for distortion free playback, and my chosen DHT tubes have the lowest distortion spectrum of audio tubes.
I've become very involved in digital playback the last 3-4 years, it is the future of audio, and DSP (digital sound processing) will enable your stereo system to get closer to the sound of real music in your home.
I have an enormous amount of respect for today's digital designers, they are taking us closer to the sound of the recording than we have ever been.
I never thought I would say this, but I expect to be listening to vinyl digitally soon- I'm presently working on a tube phono/analog to digital convertor.
Why?
In order to take advantage of DSP's amazing capabilities to perfect the speaker/room interface. Done properly (and it's not easy) this can bring vastly superior performance to the very best system.
So does the ancient tube (or valve) still have a place in this new world?
Most definitely. There is still a place for the highly evolved and ultra performance tube preamp. A modern DHT preamp has something that is very hard to describe, it brings an extra sense of realism, enhances the ambience, throws a wider, deeper soundstage and gives pin point imaging .
It's all about impedance conversion and phase performance, and its easy to confirm.
Just take the DHT tube preamp out of a digital system, and you will be connecting it back up again as fast as you can!
And for those still happy with the analog world and not using digital?
The famous Supratek phono preamps now come with DHT line stages.
I'm only making very limited amounts of preamps now, and DHT linestages are what I do best.
This year I will be building a range of DHT preamps using various selected NOS tubes -
please visit my web site www.supratek.biz for details.
Tuesday, October 29, 2013
The Future is Here Now
Last post I mentioned how pleased I was with Amarra Symphony media player.
Symphony also contains a room/speaker digital correction system, licenced from Dirac.
I guess that is why Symphony is so expensive as I presume they pay licence fees to Dirac.
I trialed Dirac, and while I liked what it did, I didn't like its in-built processor, which I thought stifled dynamics.
I thought maybe it could be a lot better combined with a good player like Amarra which is why I gave it a go.
I reported in my last post how impressed I was with the sound of Amarra in its own right, and now I can report on the integration of the room/speaker correction function , named IRC in Symphony.
It took me quite a while to figure out how to get everything functioning properly- in essence you measure the room, configure a "target" filter, which in theory fixes all your problems , apply the filter to the Amarra player and away you go.
Of course its not that simple, as choosing the right target for the room/speaker and, most importantly , your taste, takes quite a bit of trial and error.
The default suggested target has a slight downward leaning slope towards the high frequency. "Flat" response is actually not desirable at all, tending to sound a bit peaky in most systems.
I used the system first on my Lipinski studio monitors , with active subs underneath, and they actually measured very well. Indeed the suggested target was not much different from the actual measurement, and it was no surprise that with IRC switched in there was not much difference , and not worth using.
Next I tried IRC on my stacked AR-LST vintage speakers. LST stands for laboratory standard transducer , and back in the 70's and 80's they were regarded as highly accurate monitors.
They didn't measure quite as well as the Lipinski's, but still very respectable and would put most modern speakers to shame. The target filter for the AR's had a bit more correcting to do, but i couldn't find the happy medium of correction and retaining the sound I've come to enjoy with the AR's. They are driven by six tube amps, and are something I listen to for enjoyment, rather than critical listening. I could make some fine corrections with the IRC, but overall I preferred the sound unaltered.
At this stage I was ready to give up on Symphony with IRC and just buy the standard Amarra without IRC.
A friend mentioned to me that he had heard an electrostatic set up that used an OTL direct drive set up, and it was the best system he had ever heard, a big call, but I trust this guys ears, and it got me thinking to build an OTL direct drive amp for my own stats.
So I pulled the stats out from storage and set them back up to listen to while I pondered on an OTL design.
I have to say I was quite disappointed with the sound as I've gotten used to the very precise imaging and accuracy of my monitor speakers. Sure electrostatics are clear as a bell, have a big soundstage, but there is always that "electrostatic" sound, the midrange sounds just a little light , male vocals need just a bit more "weight", in comparism to a moving coil speaker. The light weight of the stat speaker certainly gives extraordinary speed and detail, and I guess like all speakers you have to acknowledge they have strengths and weakness's. And if the stat is full range, bass is compromised, and if it is a hybrid, its difficult to integrate the bass driver with the stat panel.
But before I put them away I thought I'd see how they measured in the room with Symphony. Now I suspect it has a lot to do with how stats load a room, but the measurement was not very good. So this would be a good test to see how well IRC would deal with such a problematic result.
It made a dramatic difference, in fact it was a totally different speaker, much better integration, better bass, better mids, better treble, better everything!
This was with the default target, and after a few hours listening I decided to try a different filter, as I was now beginning to better understand the relationship between target and result.
After a couple of hours I had it pretty good, and I was very impressed with my new non- electrostatic sounding speakers!
Further substantial gains were made over a couple of days using the DEQX parametric equaliser to fine tune the final sound to taste . This is very easy to do with the DEQX as one can sit in the listening position and adjust the EQ in real time.
The sound now is nothing short of very impressive, I could rabbit on about it, but I want to finish this blog so I can go and listen!
The interesting thing is that IRC really didn't do very much for accurate speakers, and yet it transformed something that I now realize was incompetent , into something that is far better in most ways than the "competent" speakers, it's certainly more interesting and enjoyable to listen to.
Perhaps conventional, accurate, well designed moving coil loudspeakers are working close to their optimal design and there is little to be gained from digital correction, apart from room influences.
It is a fact that many of the finest regarded speakers are quirky in nature- electrostatics, horn speakers, ribbons, etc - all have many enthusiasts, because they do most things well, but the same enthusiasts would admit that they have weakness's. Digital sound processing (DSP) can possibly make them near perfect, perhaps better than any "conventional" speaker. I certainly believe that electrostatic speakers benefit greatly from DSP, in my experience.
I believe DSP is the future of hi-fi, I'm an old tube guy, and I still believe there will always be a place for a tube pre-amp in any system, but DSP will make tremendous inroads into our listening experience and , importantly, pleasure.
I cant wait to see what the next few years will bring.
Like everything, it takes patience and some understanding to get the best from a system such as Symphony. Its important to understand that you still have to achieve what is subjectively "best" for your ears. There is no "correct" target , and there is no easy solution. But when it works it is sublime.
Symphony also contains a room/speaker digital correction system, licenced from Dirac.
I guess that is why Symphony is so expensive as I presume they pay licence fees to Dirac.
I trialed Dirac, and while I liked what it did, I didn't like its in-built processor, which I thought stifled dynamics.
I thought maybe it could be a lot better combined with a good player like Amarra which is why I gave it a go.
I reported in my last post how impressed I was with the sound of Amarra in its own right, and now I can report on the integration of the room/speaker correction function , named IRC in Symphony.
It took me quite a while to figure out how to get everything functioning properly- in essence you measure the room, configure a "target" filter, which in theory fixes all your problems , apply the filter to the Amarra player and away you go.
Of course its not that simple, as choosing the right target for the room/speaker and, most importantly , your taste, takes quite a bit of trial and error.
The default suggested target has a slight downward leaning slope towards the high frequency. "Flat" response is actually not desirable at all, tending to sound a bit peaky in most systems.
I used the system first on my Lipinski studio monitors , with active subs underneath, and they actually measured very well. Indeed the suggested target was not much different from the actual measurement, and it was no surprise that with IRC switched in there was not much difference , and not worth using.
Next I tried IRC on my stacked AR-LST vintage speakers. LST stands for laboratory standard transducer , and back in the 70's and 80's they were regarded as highly accurate monitors.
They didn't measure quite as well as the Lipinski's, but still very respectable and would put most modern speakers to shame. The target filter for the AR's had a bit more correcting to do, but i couldn't find the happy medium of correction and retaining the sound I've come to enjoy with the AR's. They are driven by six tube amps, and are something I listen to for enjoyment, rather than critical listening. I could make some fine corrections with the IRC, but overall I preferred the sound unaltered.
At this stage I was ready to give up on Symphony with IRC and just buy the standard Amarra without IRC.
A friend mentioned to me that he had heard an electrostatic set up that used an OTL direct drive set up, and it was the best system he had ever heard, a big call, but I trust this guys ears, and it got me thinking to build an OTL direct drive amp for my own stats.
So I pulled the stats out from storage and set them back up to listen to while I pondered on an OTL design.
I have to say I was quite disappointed with the sound as I've gotten used to the very precise imaging and accuracy of my monitor speakers. Sure electrostatics are clear as a bell, have a big soundstage, but there is always that "electrostatic" sound, the midrange sounds just a little light , male vocals need just a bit more "weight", in comparism to a moving coil speaker. The light weight of the stat speaker certainly gives extraordinary speed and detail, and I guess like all speakers you have to acknowledge they have strengths and weakness's. And if the stat is full range, bass is compromised, and if it is a hybrid, its difficult to integrate the bass driver with the stat panel.
But before I put them away I thought I'd see how they measured in the room with Symphony. Now I suspect it has a lot to do with how stats load a room, but the measurement was not very good. So this would be a good test to see how well IRC would deal with such a problematic result.
It made a dramatic difference, in fact it was a totally different speaker, much better integration, better bass, better mids, better treble, better everything!
This was with the default target, and after a few hours listening I decided to try a different filter, as I was now beginning to better understand the relationship between target and result.
After a couple of hours I had it pretty good, and I was very impressed with my new non- electrostatic sounding speakers!
Further substantial gains were made over a couple of days using the DEQX parametric equaliser to fine tune the final sound to taste . This is very easy to do with the DEQX as one can sit in the listening position and adjust the EQ in real time.
The sound now is nothing short of very impressive, I could rabbit on about it, but I want to finish this blog so I can go and listen!
The interesting thing is that IRC really didn't do very much for accurate speakers, and yet it transformed something that I now realize was incompetent , into something that is far better in most ways than the "competent" speakers, it's certainly more interesting and enjoyable to listen to.
Perhaps conventional, accurate, well designed moving coil loudspeakers are working close to their optimal design and there is little to be gained from digital correction, apart from room influences.
It is a fact that many of the finest regarded speakers are quirky in nature- electrostatics, horn speakers, ribbons, etc - all have many enthusiasts, because they do most things well, but the same enthusiasts would admit that they have weakness's. Digital sound processing (DSP) can possibly make them near perfect, perhaps better than any "conventional" speaker. I certainly believe that electrostatic speakers benefit greatly from DSP, in my experience.
I believe DSP is the future of hi-fi, I'm an old tube guy, and I still believe there will always be a place for a tube pre-amp in any system, but DSP will make tremendous inroads into our listening experience and , importantly, pleasure.
I cant wait to see what the next few years will bring.
Like everything, it takes patience and some understanding to get the best from a system such as Symphony. Its important to understand that you still have to achieve what is subjectively "best" for your ears. There is no "correct" target , and there is no easy solution. But when it works it is sublime.
Wednesday, October 9, 2013
Amarra Symphony and DHT tubes.
Amarra Symphony version 2.6 is now easily the best Computer Audio software media player.
I discovered it accidentally while researching DSP systems, and was blown over by the huge improvement in sound quality over its competitors - Audirvana Plus, JRiver etc.
I'm not sure exactly what they are doing that makes it so clearly superior, but it is by far the best digital audio I've ever heard.
"Analoge sounding" is a tired quote, but it is very apt for the sound of Symphony.
If you have ever heard a master tape on a studio quality reel to reel machine you would know that it is the most "direct" sound you can hear. Amarra Symphony has much in common with that level of sound quality.
Some of my best recordings are from the 1960's - tube microphones, tube reel to reel recording, the dynamics are startling. In many ways we have gone backwards in recording technology.
However , digital is getting better and better, and I'm sure it wont be long before those old masters are surpassed.
Of course these days everything is recorded to computer files, and then released as digital files, or burnt to a physical format such as CD or SACD.
Of all the ways to play back these files, I'm convinced that Amarra Symphony is easily the highest quality playback device currently available.
Forget sample rates, bit depths, all the techno babble, Symphony plays music!
It has faults, it's library file management is a long way behind the ease and elegance of JRiver, and its not exactly cost effective, as it is expensive.
However, I think it is worth its cost. I saw this on the Computer Audio forum as a comment on the sound quality of Symphony and I quite liked the analogy:
I hesitate because I've only had a few hours with Symphony, but I opened that can of worms now didn't I. The change is hard to described so I will resort to an analogy (surprise). The experience is akin to taking in a gorgeous view of the ocean from the comfort of your air-conditioned room. Through a perfectly clear floor to ceiling window, it's beautiful. However, when you find yourself standing on the other side holding on to the railing, it's breathtaking. The sun on your face, the heat, the breeze, the smell & roar of the ocean.. a somewhat different experience than that lovely, plush, climate-controlled room.
Amarra paints a beautiful sonic picture, one which has held me captive since first listen. The recent update to 2.6 is fabulous & I truly wondered what more could I ask for my humble system. I sincerely doubt I would have upgraded if it weren't for the new iRC component now offered in Symphony. The SQ is beyond what I expected and for me the change was immediate and palpable. I can only imagine what room correction will add. I can't wait.
Symphony will really make a substantial difference to you audio enjoyment- get it!
So what has this got to do with Directly Heated Triode (DHT) tubes?
After nearly 35 years of building with DHT tubes I know most of the tricks to get them sounding as required. Most DHT preamps, indeed most tube preamps, tend to lean towards the "tube" sound character of warm and romance. And that is what I was doing myself when I released the first commercial 6SN7/300B preamp many years ago.
Over time though it became increasingly more neutral and accurate as better designs and tube loading methods were used.
Although I dont make a 300B preamp now they are still very good sounding , if a little bloomy through the bass regions.
The 300B was replaced with the 101D, and this tube could best be described as "analytical" with very good sound-staging and imaging properties, something I came to consider just as important as the "tone" of a preamp.
My preamps were now a long way from the "warm and romantic" sound of most contemporary tube preamps, and I think that was the main reason for their success.
They still had the "magic" of tubes, that vividness and directness , but were also very accurate and full of resolution.
I used the 101D tube because it was , in my opinion, the only new production tube available that was reliable, available and suitable for preamp use.
Of course there are many other DHT tubes suitable for preamplifiers, and I've tried all of them over the years- the NOS tubes from the 1930's on can be superb (the 71A is a wonderful preamp tube) but they are very hard to find in matched and unused condition.
Lately, in a quest for the ultimate balance in tone, and the 3D effects I value so highly I've turned to Russian DHT tubes. While these are also mostly NOS they are available in quantity, and most importantly are unused and of very high construction and quality.
They've allowed me to build preamps that are of even higher resolution and accuracy, perhaps in terms of absolute performance the very best tube preamps ever built .
(I'm not the only person using these tubes, there are a handful of designers around the world having fun with the Soviet tubes)
But now we have an enigma - you certainly could not call these preamps "warm and romantic" and I suspect many tube lovers would find the sound a little challenging.
Its possible, and relatively easy to "warm" up any design , and some tubes have a tendency to sound slightly warmer - given time I can build a preamp EXACTLY to a customers taste.
But you know what? A preamp that is coloured eventually becomes boring.
A coloured preamp can be very "enjoyable" , but when a really well constructed recording is played through a system that is composed of a collection of equipment that is working optimally , in synergy, at high levels of technical proficiency , meaning accuracy and resolution at the nth degree, then the truth of the recording comes shining through, the musical soul and energy is there for you to hear and be a part of.
You cant get higher than the truth.
This is the way that Supratek preamps have evolved, so if you want a warm "tubey" sounding preamp I can build it for you, and I'm happy to do it.
But , using a superb digital front end like Amarra Symphony, an accurate DHT preamp, with similarly accurate power amps and speakers , you will never be wondering what you may be missing out on.
I discovered it accidentally while researching DSP systems, and was blown over by the huge improvement in sound quality over its competitors - Audirvana Plus, JRiver etc.
I'm not sure exactly what they are doing that makes it so clearly superior, but it is by far the best digital audio I've ever heard.
"Analoge sounding" is a tired quote, but it is very apt for the sound of Symphony.
If you have ever heard a master tape on a studio quality reel to reel machine you would know that it is the most "direct" sound you can hear. Amarra Symphony has much in common with that level of sound quality.
Some of my best recordings are from the 1960's - tube microphones, tube reel to reel recording, the dynamics are startling. In many ways we have gone backwards in recording technology.
However , digital is getting better and better, and I'm sure it wont be long before those old masters are surpassed.
Of course these days everything is recorded to computer files, and then released as digital files, or burnt to a physical format such as CD or SACD.
Of all the ways to play back these files, I'm convinced that Amarra Symphony is easily the highest quality playback device currently available.
Forget sample rates, bit depths, all the techno babble, Symphony plays music!
It has faults, it's library file management is a long way behind the ease and elegance of JRiver, and its not exactly cost effective, as it is expensive.
However, I think it is worth its cost. I saw this on the Computer Audio forum as a comment on the sound quality of Symphony and I quite liked the analogy:
I hesitate because I've only had a few hours with Symphony, but I opened that can of worms now didn't I. The change is hard to described so I will resort to an analogy (surprise). The experience is akin to taking in a gorgeous view of the ocean from the comfort of your air-conditioned room. Through a perfectly clear floor to ceiling window, it's beautiful. However, when you find yourself standing on the other side holding on to the railing, it's breathtaking. The sun on your face, the heat, the breeze, the smell & roar of the ocean.. a somewhat different experience than that lovely, plush, climate-controlled room.
Amarra paints a beautiful sonic picture, one which has held me captive since first listen. The recent update to 2.6 is fabulous & I truly wondered what more could I ask for my humble system. I sincerely doubt I would have upgraded if it weren't for the new iRC component now offered in Symphony. The SQ is beyond what I expected and for me the change was immediate and palpable. I can only imagine what room correction will add. I can't wait.
Symphony will really make a substantial difference to you audio enjoyment- get it!
So what has this got to do with Directly Heated Triode (DHT) tubes?
After nearly 35 years of building with DHT tubes I know most of the tricks to get them sounding as required. Most DHT preamps, indeed most tube preamps, tend to lean towards the "tube" sound character of warm and romance. And that is what I was doing myself when I released the first commercial 6SN7/300B preamp many years ago.
Over time though it became increasingly more neutral and accurate as better designs and tube loading methods were used.
Although I dont make a 300B preamp now they are still very good sounding , if a little bloomy through the bass regions.
The 300B was replaced with the 101D, and this tube could best be described as "analytical" with very good sound-staging and imaging properties, something I came to consider just as important as the "tone" of a preamp.
My preamps were now a long way from the "warm and romantic" sound of most contemporary tube preamps, and I think that was the main reason for their success.
They still had the "magic" of tubes, that vividness and directness , but were also very accurate and full of resolution.
I used the 101D tube because it was , in my opinion, the only new production tube available that was reliable, available and suitable for preamp use.
Of course there are many other DHT tubes suitable for preamplifiers, and I've tried all of them over the years- the NOS tubes from the 1930's on can be superb (the 71A is a wonderful preamp tube) but they are very hard to find in matched and unused condition.
Lately, in a quest for the ultimate balance in tone, and the 3D effects I value so highly I've turned to Russian DHT tubes. While these are also mostly NOS they are available in quantity, and most importantly are unused and of very high construction and quality.
They've allowed me to build preamps that are of even higher resolution and accuracy, perhaps in terms of absolute performance the very best tube preamps ever built .
(I'm not the only person using these tubes, there are a handful of designers around the world having fun with the Soviet tubes)
But now we have an enigma - you certainly could not call these preamps "warm and romantic" and I suspect many tube lovers would find the sound a little challenging.
Its possible, and relatively easy to "warm" up any design , and some tubes have a tendency to sound slightly warmer - given time I can build a preamp EXACTLY to a customers taste.
But you know what? A preamp that is coloured eventually becomes boring.
A coloured preamp can be very "enjoyable" , but when a really well constructed recording is played through a system that is composed of a collection of equipment that is working optimally , in synergy, at high levels of technical proficiency , meaning accuracy and resolution at the nth degree, then the truth of the recording comes shining through, the musical soul and energy is there for you to hear and be a part of.
You cant get higher than the truth.
This is the way that Supratek preamps have evolved, so if you want a warm "tubey" sounding preamp I can build it for you, and I'm happy to do it.
But , using a superb digital front end like Amarra Symphony, an accurate DHT preamp, with similarly accurate power amps and speakers , you will never be wondering what you may be missing out on.
Friday, August 9, 2013
New products! DHT preamps.
Been a while since my last post. Been very busy the last 6 months but still found time to do rainy day R&D and proud to present new products, and the demise of a couple of long standing old faithfuls , which is a bit sad, but the new designs are very exciting. Let me tell you about them......
Supratek was possibly the first audio company to release a Directly Heated Triode preamplifier, the first Cabernet had an option to use either a 300B, PX4 or 45 DHT tube .
Later on I went to a 101D DHT tube in the Dual Cabernet.
The Dual Cabernet was also a revolutionary product as it was the first preamp to provide 2 seperate output stages in the one chassis.
One stereo output was a 6SN7/6H30 line stage with an output impedance of 50 ohms, perfect for driving difficult solid state amps and especially useful for powering active sub-woofers. With its own seperate volume control it was the ideal device for integrating a sub woofer into a stereo system.
The main stereo preamp output used a 101D DHT tube , which is an excellent tube to use in combination with the 6SN7/6H30 , as freed of sub-sonic bass requirements , the 101D is ideal for upper bass to high frequency operation, with the wonderful ease and dynamics of DHT tubes.
There are very few new production DHT tubes suitable for pre-amplification use, the 101D is probably the best all round new production DHT preamplifier tube as it has perhaps the best sound balance of the candidates available.
Which is why other tube audio companies have started using it in the last few years.
Of course there have been many other DHT tubes available since the 1930's and my favorite tube to use in a preamp has for a long time been the 71A tube.
I've been using it for many years in my own preamps, I wish I could have offered it as an option for the Cabernet but unfortunately it hasn't been manufactured for a very long time and it is very hard to get matched pairs in pristine condition, it's taken me years to assemble a collection just for my own use.
During 2011-2013 I started using obscure NOS Russian DHT tubes in my preamps and am excited to have found some tubes that equal the sound quality of the best 1930's DHT tubes.
These are available in limited quantities, are exceptionally well built and sound fantastic!
I've purchased enough stock to build preamps and supply spare tubes, and these tubes have been incorporated into new Supratek designs that replace the circuits in the Cabernet and Cortese preamps.
I'm very pleased to be able to use a DHT tube in the Cortese phono preamp. The high quality Single Ended Class A phono stage, designed for moving coil cartridges, really deserves the best line stage. The fundamental requirements of a line stage are: a suitable gain structure and low output impedance , in order to be able to drive any power amplifier. Input impedance also plays a part.
The 6SN7 line stage used in the Cortese was an innovative and very good sounding design that ticked all the boxes, and although I was very happy with it, I would have loved to use a DHT tube. Unfortunately, there just wasn't a suitable DHT tube available to work within the confines of space and engineering in the Cortese.
Now there is!
The Russian 4P1L DHT tube is ideal as a line stage for the Cortese. Of course it has the usual state-of-the-art design which loads the tube optimally and it incorporates the feature of being able to be used as capacitor or transformer coupled output.
This gives the user a choice of gain and impedance structure, and two different types of "sound" .
Personally I feel both choices are extremely good sounding , and it is just a matter of what is best choice for your system.
The Cabernets are designed solely for line stage use and the engineering possibilities for DHT use are quite exciting.
As noted above the obvious choice for present production pre-amplification DHT tubes is the 101D.
In 2012 the design of the Cabernets changed from directly coupling the 6SN7 driver tube to the 101D, in favour of capacitor coupling , in combination with grid chokes , and the use of exotic Lundahl output transformers.
This form of circuit enables a different type of bias which we label LowR , the primary advantage of which is to negate the need for large capacitance decoupling and bypass caps, the source of "veiling" in many tube preamps.
This greatly enhanced what I consider most important in pre-amplification- the ability to throw a realistic soundstage with realistic 3D imaging, (depth and width), with dynamics that show greater expression of micro and macro layers.
Vividness is a term I've been using to describe the Supratek sound for many years, and with the new DHT designs it is again enhanced.
It has been very exciting to me to be able to source DHT tubes with the quality and sound characteristics of the DHT tubes produced in the "golden age" of tube manufacture and design , the period from 1920- 1960.
While the Western electronics industry veered towards low cost, high production solid state technology that promised high profits, the Russian tube manufacturers refined and developed very high quality tube products that matched and exceeded the best tubes available from the West.
Of all the Russian DHT tubes I've tested and experimented with over the last few years my favourites are the 4P1L and 6P21S, which are both multi-grid low power tubes, however, connected as triodes they are superb preamp tubes with low impedance and ideal gain. To find a tube that sounds as good as the best 71A is very satisfying.
The Cabernet Dual is the premier preamp in the Supratek line up. The 6SN7/6H30 output stays the same , but the 101D tube is replaced by the 6P21S for a fuller sound that seems more musical, yet as detailed and of higher resolution than the 101D.
The 6P21S has a greater range then the 101D, the bass of the 6P21S is deep and tight, yet it also has exceptional mid and treble sound.
Only the highest quality parts and components are used- Lundahl and Magnequest transformers and grid chokes. Capacitors are paper-in-oil, chosen to compliment the sonic signature of the preamp.
The tremendous advantage of the Cabernets shunt regulated power supply remains, and the overkill size of power transformers means the Cabernet electronics perform quietly and effortlessly .
The chassis's are still fabricated from 1.2mm solid copper, far more important than it seems, and covered with high quality chrome or powder coat.
The Cabernet Single is exactly the same without the 6H30 driver output.
(BTW the The 6H30 driver in the Dual Cabernet can also be used as a valve output stage for suitable dacs)
Supratek hasn't been a "conventional" retail audio manufacturer for a long time, I dont depend on it for income and the reason for Supratek's existence is more about a passion for high end tube electronics than a commercial venture.
The (small) profit from preamp sales goes back into R&D- for every 3 or 4 preamps sold there would be at least one prototype built to investigate a new concept or idea.
I have a lifetime's experience of DHT use for preamps, and my passion for DHT preamps is stronger than ever before, even with so called claims for the demise of preamps as they supposedly are not needed with digital devices.
This is rubbish and reflects poor equipment and listening skills, or perhaps the claimants have just never heard a good tube preamp. It is true that good tube preamps are rare, but a good tube preamp will be the heart and soul of a system that takes you to the essence of the music.
Because the Supratek preamps are completely handmade, and it is not a commercial profit making venture , very few are actually built.
I've found it impossible to supply worldwide demand and as a consequence the Chardonnay, Sauvignon, and Grange preamps will no longer be built.
The Chenin will continue for a little while longer and then I will be concentrating on only building Cabernet and Cortese DHT preamps, as I am available.
The reliability and very long life time of the Cabernet and Cortese is something I take very seriously. New models are not regularly introduced and there is a great deal of thought and commitment to longevity. A classic tube product should last 50 years and more.
Directly Heated Triode Preamps are the pinnacle of preamp design and I hope to be able to continue to enrich the musical lives of future owners.
Supratek was possibly the first audio company to release a Directly Heated Triode preamplifier, the first Cabernet had an option to use either a 300B, PX4 or 45 DHT tube .
Later on I went to a 101D DHT tube in the Dual Cabernet.
The Dual Cabernet was also a revolutionary product as it was the first preamp to provide 2 seperate output stages in the one chassis.
One stereo output was a 6SN7/6H30 line stage with an output impedance of 50 ohms, perfect for driving difficult solid state amps and especially useful for powering active sub-woofers. With its own seperate volume control it was the ideal device for integrating a sub woofer into a stereo system.
The main stereo preamp output used a 101D DHT tube , which is an excellent tube to use in combination with the 6SN7/6H30 , as freed of sub-sonic bass requirements , the 101D is ideal for upper bass to high frequency operation, with the wonderful ease and dynamics of DHT tubes.
There are very few new production DHT tubes suitable for pre-amplification use, the 101D is probably the best all round new production DHT preamplifier tube as it has perhaps the best sound balance of the candidates available.
Which is why other tube audio companies have started using it in the last few years.
Of course there have been many other DHT tubes available since the 1930's and my favorite tube to use in a preamp has for a long time been the 71A tube.
I've been using it for many years in my own preamps, I wish I could have offered it as an option for the Cabernet but unfortunately it hasn't been manufactured for a very long time and it is very hard to get matched pairs in pristine condition, it's taken me years to assemble a collection just for my own use.
During 2011-2013 I started using obscure NOS Russian DHT tubes in my preamps and am excited to have found some tubes that equal the sound quality of the best 1930's DHT tubes.
These are available in limited quantities, are exceptionally well built and sound fantastic!
I've purchased enough stock to build preamps and supply spare tubes, and these tubes have been incorporated into new Supratek designs that replace the circuits in the Cabernet and Cortese preamps.
I'm very pleased to be able to use a DHT tube in the Cortese phono preamp. The high quality Single Ended Class A phono stage, designed for moving coil cartridges, really deserves the best line stage. The fundamental requirements of a line stage are: a suitable gain structure and low output impedance , in order to be able to drive any power amplifier. Input impedance also plays a part.
The 6SN7 line stage used in the Cortese was an innovative and very good sounding design that ticked all the boxes, and although I was very happy with it, I would have loved to use a DHT tube. Unfortunately, there just wasn't a suitable DHT tube available to work within the confines of space and engineering in the Cortese.
Now there is!
The Russian 4P1L DHT tube is ideal as a line stage for the Cortese. Of course it has the usual state-of-the-art design which loads the tube optimally and it incorporates the feature of being able to be used as capacitor or transformer coupled output.
This gives the user a choice of gain and impedance structure, and two different types of "sound" .
Personally I feel both choices are extremely good sounding , and it is just a matter of what is best choice for your system.
DHT Cortese 4P1L tube at back
The Cabernets are designed solely for line stage use and the engineering possibilities for DHT use are quite exciting.
As noted above the obvious choice for present production pre-amplification DHT tubes is the 101D.
In 2012 the design of the Cabernets changed from directly coupling the 6SN7 driver tube to the 101D, in favour of capacitor coupling , in combination with grid chokes , and the use of exotic Lundahl output transformers.
This form of circuit enables a different type of bias which we label LowR , the primary advantage of which is to negate the need for large capacitance decoupling and bypass caps, the source of "veiling" in many tube preamps.
This greatly enhanced what I consider most important in pre-amplification- the ability to throw a realistic soundstage with realistic 3D imaging, (depth and width), with dynamics that show greater expression of micro and macro layers.
Vividness is a term I've been using to describe the Supratek sound for many years, and with the new DHT designs it is again enhanced.
It has been very exciting to me to be able to source DHT tubes with the quality and sound characteristics of the DHT tubes produced in the "golden age" of tube manufacture and design , the period from 1920- 1960.
While the Western electronics industry veered towards low cost, high production solid state technology that promised high profits, the Russian tube manufacturers refined and developed very high quality tube products that matched and exceeded the best tubes available from the West.
Of all the Russian DHT tubes I've tested and experimented with over the last few years my favourites are the 4P1L and 6P21S, which are both multi-grid low power tubes, however, connected as triodes they are superb preamp tubes with low impedance and ideal gain. To find a tube that sounds as good as the best 71A is very satisfying.
The Cabernet Dual is the premier preamp in the Supratek line up. The 6SN7/6H30 output stays the same , but the 101D tube is replaced by the 6P21S for a fuller sound that seems more musical, yet as detailed and of higher resolution than the 101D.
The 6P21S has a greater range then the 101D, the bass of the 6P21S is deep and tight, yet it also has exceptional mid and treble sound.
Only the highest quality parts and components are used- Lundahl and Magnequest transformers and grid chokes. Capacitors are paper-in-oil, chosen to compliment the sonic signature of the preamp.
The tremendous advantage of the Cabernets shunt regulated power supply remains, and the overkill size of power transformers means the Cabernet electronics perform quietly and effortlessly .
The chassis's are still fabricated from 1.2mm solid copper, far more important than it seems, and covered with high quality chrome or powder coat.
All Supratek preamps, and power supplies, are made from 1.2mm copper.
The Cabernet Single is exactly the same without the 6H30 driver output.
(BTW the The 6H30 driver in the Dual Cabernet can also be used as a valve output stage for suitable dacs)
Supratek hasn't been a "conventional" retail audio manufacturer for a long time, I dont depend on it for income and the reason for Supratek's existence is more about a passion for high end tube electronics than a commercial venture.
The (small) profit from preamp sales goes back into R&D- for every 3 or 4 preamps sold there would be at least one prototype built to investigate a new concept or idea.
I have a lifetime's experience of DHT use for preamps, and my passion for DHT preamps is stronger than ever before, even with so called claims for the demise of preamps as they supposedly are not needed with digital devices.
This is rubbish and reflects poor equipment and listening skills, or perhaps the claimants have just never heard a good tube preamp. It is true that good tube preamps are rare, but a good tube preamp will be the heart and soul of a system that takes you to the essence of the music.
Because the Supratek preamps are completely handmade, and it is not a commercial profit making venture , very few are actually built.
I've found it impossible to supply worldwide demand and as a consequence the Chardonnay, Sauvignon, and Grange preamps will no longer be built.
The Chenin will continue for a little while longer and then I will be concentrating on only building Cabernet and Cortese DHT preamps, as I am available.
The reliability and very long life time of the Cabernet and Cortese is something I take very seriously. New models are not regularly introduced and there is a great deal of thought and commitment to longevity. A classic tube product should last 50 years and more.
Directly Heated Triode Preamps are the pinnacle of preamp design and I hope to be able to continue to enrich the musical lives of future owners.
Thursday, May 9, 2013
Update Sonic Panel Electrostatics
http://supratekaudio.blogspot.com.au/2012/11/an-inexpensive-top-quality.html
They're really quite capable as singles but stacking two pairs gives even greater sensitivity and a larger dispersion, which gives a bigger , more open sound.
I had some speaker frames made up by a furniture craftsman (John Thompson Designs in Bussellton) to give some weight and solidity to the set up.
The sub/woofer remains the same, an Acoustic Elegance 18" driver which has the ability to remain linear up to well over the crossover point of 400Hz.
I chose this higher point to give a bit more solidity to the crossover region as it did sound a little weaker there with the extra sensitivity of the stats.
Amps remain solid state high power, pre is tube (of course!) active crossover is either digital or a op-amp version I'm experimenting with.
Once I found the optimal crossover points I'll build a tube crossover .
One new feature is the use of a parametric equaliser program incorporated into the computer audio program I use for playback.
Fabfilter Pro-Q used with JRiver Media Centre 18 is really exceptional- easy to use, very versatile, and operating at 64 bit , it sounds very good.
(For Mac it can be used with PureMusic)
I prefer it to the sound of the parametric functions in the digital crossovers I use (DEQX and DBX PA) and its much quicker and easier to use.
Heres a screen shot of one of the settings I used to determine EQ for the large workshop the speakers are presently in. Final settings will be not as dramatic, but a very powerful tool.
The sound of the stacked stats is very good, they have a real ability for a big sound, and for their size have remarkable dynamics and power.
Active operation and EQ is the best option to get them at their best, I would imagine it would be very time consuming to build passive crossovers to suit.
They are too good for my workshop, but enjoyable to listen to while working.
Wednesday, May 8, 2013
"Euphonic" Tubes
There is a perception widely held that tubes have a more "euphonic" sound than solid state devices, that they sound "warmer, lusher, more romantic".
Its a common theme on the audio forums and you see this perception of "euphonics" very frequently, and often from people who have been in audio for a long time.
"Use a tube buffer to soften the sound" or "use a XXXX type of tube for a lovely lush tone".
This type of perception is very misguided and completely wrong.
Let me explain why.
Firstly the term buffer can be applied to either tubes or solid state. The term is correctly used as a non-amplifying device (no gain) which couples two devices so they can work optimally together. If you have an amplifier with a lowish input impedance and a source with highish output impedance , combined together they will probably have a degraded frequency response.
You need a "buffer" to couple these devices together, something that will present an agreeable load to the source and the amplifier.
The most common devices are opamps, usually used on the outputs of CDP, DACs, etc.
The problem with opamps are they are 100% feedback devices, they do a very good job technically , but they sure leave a lot to be desired in respect to sound quality.
Good designers often revert to discrete designs that require much less levels of feedback.
(There are design methods and types of opamps that sound good, but rare)
Or some people say "use a tube buffer- much better than opamps".
A tube buffer that has no gain is usually a design known as a cathode follower, it has just less than a gain of 1 (unity gain) and has high input impedance and low output impedance which is ideal, but like an an opamp it has 100% degenerative feedback.
It is possible to make a tube buffer sound ok, but all the tube buffers tacked on to the back of dacs , preamps etc are no better than the opamps they are supposed to improve on, and in many cases are inferior.
Its easy to tack a tube on the back of a solid state design, but many solid state designers do not understand tube design, and follow a tired formula to get some tube "credibility".
It is quite common to see many tube buffers used at far lower voltages than they need for optimum operating conditions, and the tube is struggling to do its job.
The cathode follower design is commonly used because it allows a tube that can not normally be used for buffering to have a low enough output impedance to do the job.
But remember, like an opamp it is a 100% feedback device.
What determines how well a tube can drive a following stage is its Plate Resistance (Pr)
If a tube has a high plate resistance, and used in a zero feedback design (nice) it will have a high output resistance (Z).
Tubes like the 12AX7, 6SL7, 12AT7, etc have Pr in the range 50-100Kohm and also have very high gain.
They cant be used as buffers as they have too much gain, and no drive ability. They are high gain devices very much limited to specific use.
These devices when used as amplifying/buffering devices really do have the "warm, lush and romantic" sound of tubes, because they are not operating as they were designed for.
Tubes with medium Pr like the 6SN7, 12AU7, 12BH7, etc have Pr around 5K ohms, and are better at driving loads. You could use one of these tubes to drive a reasonable load of 100Kohms, or higher, but not much lower, they struggle with power amps of lowish input Z . Typically they have medium gain, usually too much to use as non-amplifying buffers, and they are not ideal as buffers anyway.
Depending on the situation the sound can have varying degrees of "euphonics".
An ideal input/output ratio is a minimum of 10 . A preamp with output Z of 10K will be just ok with a power amp's input Z of 100K, although the lower the better.
The higher the ratio the better the performance, and generally speaking, the accuracy will increase and tube "euphonics" will be reduced.
Tubes such as the 12B4A, 6H30, D3a, etc have low Pr around 1-2Kohms and are ideal as interfaces between devices. They have extremely low distortion, provide accurate driving conditions and are ideal used as buffers, although depending on the tube and operating points there will be gain.
Some of the DHT tubes are also ideal in this situation, although a bit more finicky to use.
Some really good tubes were designed at the end of the tube era, high gain and low Pr was a difficult, almost impossible task in the early 19th century but by the 60/70's some excellent tubes were designed- the D3a, E810F, E280F and many others had very high gain, and also low Pr, really the perfect amplifying device.
It should be mentioned that the operating points of all tubes is critical to performance, the level of harmonic distortion plays a major part in any tubes sound, for good and bad, and the designer needs to adjust for the performance required.
Many "lush" circuits are the direct result of improper operating points, sometimes done deliberately, eg guitar amps, SE amplifiers.
It should also be noted that feedback is not necessarily a "bad" thing, feedback that is used to fix design or component faults is always counter-productive, but used sparingly and wisely , it can be a powerful and good sounding tool.
Feedback can be especially useful with high and medium Pr tubes as it lowers the Pr and output Z of these tubes.
Naturally I like tubes in my preamps and as the devices on the output stages of my dacs, I think for dac outputs the low Pr tubes are very much ideal and have very much better sound than any opamp or other discrete device (although I do have a fondness for j-fets).
There are no "euphonics" with the low Pr tubes if used properly- they have very low levels of distortion, are accurate, clean and powerful sounding , very much broadcasting the fact that they are completely zero-feedback, which leads to very good phase performance, and that can be heard in excellent sound-staging and imaging.
But how to get the unity gain that is required in this situation without using a 100% feedback "tube buffer" (also referred to as a goats turd) when I typically use a low Pr tube with a gain of up to 50?
Fortunately the dac often needs some amplification, but the best option is to use a step-down transformer which brings the gain down to useable levels, and lowers the output Z even further.
It is imperative to use a high-bandwidth device that is matched to the tube used, and these devices are expensive. I use Magnequest, Lundahl and Jensen transformers, all imported.
There are different methods of loading the plate resistance of the tube, and many different methods of biasing the tubes.
In fact there are so many variables to tube design, it does take many years of experience to sort the best designs from the less desirable.
But the advantages are very worthwhile and it is very hard to listen to an op-amp buffered dac after living with a good tube output stage that is not a 100% feedback tube buffer.
"Euphonics" has its place , but preferably in a glass of wine, or your choice of ecstacy.
Of course there are many who actually prefer the sound of euphonic systems, actively chasing "warm and lush" sounds.
In todays hi-resolution world, that is perhaps illusionary , but each to his own, and I can quite readily enjoy such a system for a limited time
Here is one of my preamps, used as an example of tube selection and the reasons.
The bigger tubes at the back are 71A Directly Heated Triodes. These are actually very low power tubes, used back in the 30's in radios, but with a low Pr and low gain they are ideal for driving modern power amps. DHT's are finicky to use in terms of noise and minimal components, but there are ways around this. They are used with output transformers so gain is very low, to counter this I use a pair of 6SN7 medium Pr tubes (on the outside) to provide gain. They see an easy load to the 71A's and need a simple non-feedback circuit to drive the 71A's.
The inside tubes are E280F's which are used to provide a separate tube gain stage for one of my dacs. The output from the dac chip is fed straight into the E280F and the output can be switched into the line stage. The E280F is chosen as it is a high gain/low Pr tube. It is transformer coupled and makes an excellent compliment to the digital-to-analouge conversion.
Its a common theme on the audio forums and you see this perception of "euphonics" very frequently, and often from people who have been in audio for a long time.
"Use a tube buffer to soften the sound" or "use a XXXX type of tube for a lovely lush tone".
This type of perception is very misguided and completely wrong.
Let me explain why.
Firstly the term buffer can be applied to either tubes or solid state. The term is correctly used as a non-amplifying device (no gain) which couples two devices so they can work optimally together. If you have an amplifier with a lowish input impedance and a source with highish output impedance , combined together they will probably have a degraded frequency response.
You need a "buffer" to couple these devices together, something that will present an agreeable load to the source and the amplifier.
The most common devices are opamps, usually used on the outputs of CDP, DACs, etc.
The problem with opamps are they are 100% feedback devices, they do a very good job technically , but they sure leave a lot to be desired in respect to sound quality.
Good designers often revert to discrete designs that require much less levels of feedback.
(There are design methods and types of opamps that sound good, but rare)
Or some people say "use a tube buffer- much better than opamps".
A tube buffer that has no gain is usually a design known as a cathode follower, it has just less than a gain of 1 (unity gain) and has high input impedance and low output impedance which is ideal, but like an an opamp it has 100% degenerative feedback.
It is possible to make a tube buffer sound ok, but all the tube buffers tacked on to the back of dacs , preamps etc are no better than the opamps they are supposed to improve on, and in many cases are inferior.
Its easy to tack a tube on the back of a solid state design, but many solid state designers do not understand tube design, and follow a tired formula to get some tube "credibility".
It is quite common to see many tube buffers used at far lower voltages than they need for optimum operating conditions, and the tube is struggling to do its job.
The cathode follower design is commonly used because it allows a tube that can not normally be used for buffering to have a low enough output impedance to do the job.
But remember, like an opamp it is a 100% feedback device.
What determines how well a tube can drive a following stage is its Plate Resistance (Pr)
If a tube has a high plate resistance, and used in a zero feedback design (nice) it will have a high output resistance (Z).
Tubes like the 12AX7, 6SL7, 12AT7, etc have Pr in the range 50-100Kohm and also have very high gain.
They cant be used as buffers as they have too much gain, and no drive ability. They are high gain devices very much limited to specific use.
These devices when used as amplifying/buffering devices really do have the "warm, lush and romantic" sound of tubes, because they are not operating as they were designed for.
Tubes with medium Pr like the 6SN7, 12AU7, 12BH7, etc have Pr around 5K ohms, and are better at driving loads. You could use one of these tubes to drive a reasonable load of 100Kohms, or higher, but not much lower, they struggle with power amps of lowish input Z . Typically they have medium gain, usually too much to use as non-amplifying buffers, and they are not ideal as buffers anyway.
Depending on the situation the sound can have varying degrees of "euphonics".
An ideal input/output ratio is a minimum of 10 . A preamp with output Z of 10K will be just ok with a power amp's input Z of 100K, although the lower the better.
The higher the ratio the better the performance, and generally speaking, the accuracy will increase and tube "euphonics" will be reduced.
Tubes such as the 12B4A, 6H30, D3a, etc have low Pr around 1-2Kohms and are ideal as interfaces between devices. They have extremely low distortion, provide accurate driving conditions and are ideal used as buffers, although depending on the tube and operating points there will be gain.
Some of the DHT tubes are also ideal in this situation, although a bit more finicky to use.
Some really good tubes were designed at the end of the tube era, high gain and low Pr was a difficult, almost impossible task in the early 19th century but by the 60/70's some excellent tubes were designed- the D3a, E810F, E280F and many others had very high gain, and also low Pr, really the perfect amplifying device.
It should be mentioned that the operating points of all tubes is critical to performance, the level of harmonic distortion plays a major part in any tubes sound, for good and bad, and the designer needs to adjust for the performance required.
Many "lush" circuits are the direct result of improper operating points, sometimes done deliberately, eg guitar amps, SE amplifiers.
It should also be noted that feedback is not necessarily a "bad" thing, feedback that is used to fix design or component faults is always counter-productive, but used sparingly and wisely , it can be a powerful and good sounding tool.
Feedback can be especially useful with high and medium Pr tubes as it lowers the Pr and output Z of these tubes.
Naturally I like tubes in my preamps and as the devices on the output stages of my dacs, I think for dac outputs the low Pr tubes are very much ideal and have very much better sound than any opamp or other discrete device (although I do have a fondness for j-fets).
There are no "euphonics" with the low Pr tubes if used properly- they have very low levels of distortion, are accurate, clean and powerful sounding , very much broadcasting the fact that they are completely zero-feedback, which leads to very good phase performance, and that can be heard in excellent sound-staging and imaging.
But how to get the unity gain that is required in this situation without using a 100% feedback "tube buffer" (also referred to as a goats turd) when I typically use a low Pr tube with a gain of up to 50?
Fortunately the dac often needs some amplification, but the best option is to use a step-down transformer which brings the gain down to useable levels, and lowers the output Z even further.
It is imperative to use a high-bandwidth device that is matched to the tube used, and these devices are expensive. I use Magnequest, Lundahl and Jensen transformers, all imported.
There are different methods of loading the plate resistance of the tube, and many different methods of biasing the tubes.
In fact there are so many variables to tube design, it does take many years of experience to sort the best designs from the less desirable.
But the advantages are very worthwhile and it is very hard to listen to an op-amp buffered dac after living with a good tube output stage that is not a 100% feedback tube buffer.
"Euphonics" has its place , but preferably in a glass of wine, or your choice of ecstacy.
Of course there are many who actually prefer the sound of euphonic systems, actively chasing "warm and lush" sounds.
In todays hi-resolution world, that is perhaps illusionary , but each to his own, and I can quite readily enjoy such a system for a limited time
Here is one of my preamps, used as an example of tube selection and the reasons.
The bigger tubes at the back are 71A Directly Heated Triodes. These are actually very low power tubes, used back in the 30's in radios, but with a low Pr and low gain they are ideal for driving modern power amps. DHT's are finicky to use in terms of noise and minimal components, but there are ways around this. They are used with output transformers so gain is very low, to counter this I use a pair of 6SN7 medium Pr tubes (on the outside) to provide gain. They see an easy load to the 71A's and need a simple non-feedback circuit to drive the 71A's.
The inside tubes are E280F's which are used to provide a separate tube gain stage for one of my dacs. The output from the dac chip is fed straight into the E280F and the output can be switched into the line stage. The E280F is chosen as it is a high gain/low Pr tube. It is transformer coupled and makes an excellent compliment to the digital-to-analouge conversion.
Sunday, April 28, 2013
AR-LST speakers "activated"
I've sold most along the way, but some of the real classics are of such quality I've kept them in my store.
Around 2008 I bought 2 pairs of the Acoustic Research AR-LST from a little old lady's son after she become too old to manage them. I don't know why she needed 2 pairs, but they were in perfect condition and I paid $4000 for them, which was quite a lot for speakers made in 1975.
I knew of the formidable reputation the Laboratory Standard Transducers (LST) had and loaded all 160 kgs into my car.
The LST's are an unusual speaker with multi-drivers. One 12" bass driver in a sealed cabinet, 4 of one and a half inch midrange dome drivers and 4 of three quarter of an inch dome tweeters.
The cabinet has two offset side panels which contain the midrange and 2 of the tweeter units.
Kind of like a Bose 901 cabinet, but much bigger and meaner!
With the 2 pairs stacked I have a total of 36 drivers playing. I've always believed that small speakers are a compromise and for realistic sound a speaker has to have the physicality to move lots of air, hence my love of big stats, horns and big moving coil speakers.
The crossovers in the LST are quite interesting, 12dB slopes at 575 and 5000Hz. Nice big air coils and quality caps , I only needed to replace the midrange electrolytic cap for a poly cap.
The speaker had an input transformer with many taps to alter the tonal frequency, to adjust for room response and taste. Unfortunately this required a 2500uF electrolytic cap to counter sub bass resonance and I can't say I was too happy about having this in the signal path.
As I intended to actively tri-amp I had no need for level adjustment and rebuilt the crossovers on the back panel of the cabinet, removing the transformer and hardwiring all the crossover components .
The printed circuit boards also went in the bin.
I also put an extra set of speaker connectors for each set of drivers on back panel so that I could either use the passive crossovers or run the drivers directly from the seperate amps I intended to use for bass, mid and treble, utilizing an active crossover, either analogue or digital.
With this set up I could choose whatever types of amps I wanted to use with either the bass, mid and treble sets of drivers.
The AR-LST's came along at a defining moment in amplifier design- the new high power solid state designs had just replaced the tube designs of the 50's/60's and the LST was a difficult load- it needed the high power and current abilities of the solid state amps, but these new designs typically used a lot of negative feedback and were not the nicest sounding amps. Amps like the Crown DC300 were commonly used and the results were not in the LST's favour.
Modern day solid state amps fare much better, but part of this restoration was to enable me to use my tube power amps with this speaker.
Dividing the crossover into 3 separate sections- bass, mid and treble makes the amplifiers load much easier and I was positive my tube amps, which use positive current feedback would drive the LST's very well.
The only question was would they also drive two sets of speakers, in parallel and with the passive crossovers presenting a heavy load.
Fortunately it was not a problem, and the amps have no problem at all in driving the LST's cleanly at high levels.
I'm using a 100watt KT88 ultra-linear amp on bass, an 80 watt KT88 triode amp on mids and a 60 watt 7027 pentode amp on treble, all with positive current current.
I've been using current feedback on all my amps for many years now and it is interesting to see positive feedback now becoming used by quite a few well respected tube designers- its a win/win design that enables tube amps to work exceedingly well with just about any difficult speaker.
I've been a fan of digital crossovers for around 5 years, owning DEQX and DBX active digital crossovers, but I must admit I'm enjoying the passive crossover/ tri-amping approach used on the LST's.
My big reference electrostatic system demands solid state amplification and I somewhat miss the use of an all tube system, but with the LST's use of 6 tube power amps and a tube preamp , I am in tube heaven!
Incidentally I also went away from using a digital crossover in my big reference system, and built the speaker crossover function into the tube preamp, which works very well.
I dont think there is anything wrong with digital crossovers, but getting tubes or passive components to do the job if possible makes it simple, and simple is often better.
Although it is obvious that 6 monoblock power amps is not exactly simplistic!
I'm very happy with the AR-LST sound, it has the big dynamic openness I like, and is completely natural and un-restrained sounding. It is the type of sound you can listen to indefinitely and is simply very enjoyable.
Used in this fashion the LST's almost sound like a cross of moving coil, electrostatic and horn speakers- they have something of the good points of all 3, even a touch of ribbon sound to them.
This is the beauty of active amplification- the finest of adjustments can be made to the levels of each crossover function and the system can be precisely fine tuned to suit the owners room and taste.
Sunday, November 25, 2012
Reference System Dec 2012
My reference system has changed again, not surprisingly I suppose, as I'm inclined to finding incremental improvements that make the listening experience a little more satisfying.
Inputs:
1.Fanless PC built and optimized solely for audio, Windows/JRiver player program, up sampling to 352.8 or 384 KHz, Exa U2I USB-I2S convertor into Ackodac Sabre dac, seperate tube output stage using 7788 tubes, heater bias, tube shunt regulation, Magnequest output trans.
2. Luxman PD-444 turntable , Dynavector DV-505 arm with Ortofon SPU cartridge modified with Expert Stylus cantilever and stylus. FR-64 arm with Accuphase AC-1 cartridge modified with Expert Stylus cantilever and stylus.
No CD, or spdif inputs- they are a dead end to my ears.
Pre-amplification
6SN7/71A DHT preamp with built in 12dB crossover at 220Hz, 6H30 tubes drive bass outputs.
Power-amplification
Carver Sunfire 5 channel power amp capable of greater than 1000 watts/1 ohm into all channels.
Speakers
MartinLogan Request electrostatic hybrid speakers with 12" sealed bass drivers, passive crossovers removed, crossover provided by preamp.
DSP
DSPeaker Anti-Mode 8033s Bass correction with Wharfdale 10" subwoofer.
Description:
The Exa-U2I usb to I2S convertor remains my choice of digital source , I haven't heard anything over the last 6 months that surpasses it yet. Similarly the Ackodac remains at the forefront of digital dac design, I expect something quite different and better every day, things change fast in digital land, but it will have to be audibly better for a change. I've tried some new devices but no reason to change yet.
Vinyl stays the same, why change what is very satisfying, although waiting on some Lundahl chokes to try a new LCR RIAA phono design.
The preamp is new, I've shifted the DEQX digital crossover to another system and now using a preamp with inbuilt crossover for 4 channel output, 220Hz @ 12dB . The upper frequencies come from a 6SN7/71A tube stage and 6H30's for the bass. No cathode followers in the12dB filter sections. Phono uses 6688,CCa and 6E6P tubes.
Another change is I've gone back to using a solid state high current capable power amp.
I was quite happy with the 4 monoblock tube amps, but, I listen to a diverse range of music from opera to electric blues, and usually I play everything LOUD. My listening studio is rural and private and I like the dynamics of live-like sound.
Tube amps, especially the low output impedance amps I build can drive normal speakers to these levels, but electrostatics simply need very high power levels, especially into the higher frequencies where the stats load drops dramatically.
My favorite all time solid state amp, the Carver Sunfire can deliver more than a 1000 watts into 1 ohm, from all 4 channels.
Some very distinguished hi fi critics have said the the Carver Sunfire is nearly the perfect amplifier, and as far as electrostatics go it is hard to find anything better. Super reliable too.
Speakers remain the same, Martin Logan Requests, new panels and the dynamic robbing passive crossovers removed.
The 12" bass drivers used in sealed boxes were perhaps ML's best solution to integrating bass with the stat panels and retaining deep solid bass.
These speakers are not the polite, dynamically restricted stats people used to Quads etc know. They can play at very loud concert levels with any kind of music, always exciting, never tiring. It always with a tinge of regret when its time to stop listening to the music.
The DSPeaker Anti-Mode 8033s is new- it is designed to remove bass standing waves and works in conjunction with an additional sub-woofer to clean up the bass. It doesn't really extend the bass, the ML's have quite good bass extension, but it does a great job of tightening and cleaning up the lower bass.
The systems only real flaw is that the speakers are very directional and the sweet spot is very tight- move 6" either way and the sound-staging and imaging go 2 dimensional, but I usually enjoy my music alone so no problem for me, I have a well-worn arse-groove in the perfect position. The stat panels I'm currently evaluating (see previous post) are much better in this regard and stacked panels may eventually replace the ML panels.
Inputs:
1.Fanless PC built and optimized solely for audio, Windows/JRiver player program, up sampling to 352.8 or 384 KHz, Exa U2I USB-I2S convertor into Ackodac Sabre dac, seperate tube output stage using 7788 tubes, heater bias, tube shunt regulation, Magnequest output trans.
2. Luxman PD-444 turntable , Dynavector DV-505 arm with Ortofon SPU cartridge modified with Expert Stylus cantilever and stylus. FR-64 arm with Accuphase AC-1 cartridge modified with Expert Stylus cantilever and stylus.
No CD, or spdif inputs- they are a dead end to my ears.
Pre-amplification
6SN7/71A DHT preamp with built in 12dB crossover at 220Hz, 6H30 tubes drive bass outputs.
Power-amplification
Carver Sunfire 5 channel power amp capable of greater than 1000 watts/1 ohm into all channels.
Speakers
MartinLogan Request electrostatic hybrid speakers with 12" sealed bass drivers, passive crossovers removed, crossover provided by preamp.
DSP
DSPeaker Anti-Mode 8033s Bass correction with Wharfdale 10" subwoofer.
Description:
The Exa-U2I usb to I2S convertor remains my choice of digital source , I haven't heard anything over the last 6 months that surpasses it yet. Similarly the Ackodac remains at the forefront of digital dac design, I expect something quite different and better every day, things change fast in digital land, but it will have to be audibly better for a change. I've tried some new devices but no reason to change yet.
Vinyl stays the same, why change what is very satisfying, although waiting on some Lundahl chokes to try a new LCR RIAA phono design.
The preamp is new, I've shifted the DEQX digital crossover to another system and now using a preamp with inbuilt crossover for 4 channel output, 220Hz @ 12dB . The upper frequencies come from a 6SN7/71A tube stage and 6H30's for the bass. No cathode followers in the12dB filter sections. Phono uses 6688,CCa and 6E6P tubes.
Another change is I've gone back to using a solid state high current capable power amp.
I was quite happy with the 4 monoblock tube amps, but, I listen to a diverse range of music from opera to electric blues, and usually I play everything LOUD. My listening studio is rural and private and I like the dynamics of live-like sound.
Tube amps, especially the low output impedance amps I build can drive normal speakers to these levels, but electrostatics simply need very high power levels, especially into the higher frequencies where the stats load drops dramatically.
My favorite all time solid state amp, the Carver Sunfire can deliver more than a 1000 watts into 1 ohm, from all 4 channels.
Some very distinguished hi fi critics have said the the Carver Sunfire is nearly the perfect amplifier, and as far as electrostatics go it is hard to find anything better. Super reliable too.
Speakers remain the same, Martin Logan Requests, new panels and the dynamic robbing passive crossovers removed.
The 12" bass drivers used in sealed boxes were perhaps ML's best solution to integrating bass with the stat panels and retaining deep solid bass.
These speakers are not the polite, dynamically restricted stats people used to Quads etc know. They can play at very loud concert levels with any kind of music, always exciting, never tiring. It always with a tinge of regret when its time to stop listening to the music.
The DSPeaker Anti-Mode 8033s is new- it is designed to remove bass standing waves and works in conjunction with an additional sub-woofer to clean up the bass. It doesn't really extend the bass, the ML's have quite good bass extension, but it does a great job of tightening and cleaning up the lower bass.
The systems only real flaw is that the speakers are very directional and the sweet spot is very tight- move 6" either way and the sound-staging and imaging go 2 dimensional, but I usually enjoy my music alone so no problem for me, I have a well-worn arse-groove in the perfect position. The stat panels I'm currently evaluating (see previous post) are much better in this regard and stacked panels may eventually replace the ML panels.
Friday, November 9, 2012
An inexpensive top quality Electrostatic speaker kit
The people who designed and commissioned the Nakamichi Dragon electrostatic speaker build (which I rate highly, see previous post) , are making a stat panel driver available that is based on the same technology used in the Dragons.
http://www.involveaudio.com/audio.php?id=33&pid=10
The speaker evaluation kit contains a pair of panels, a step up transformer and a DC power supply , essentially everything you need for a speaker to work from its lower frequency response of around 200Hz to 20Khz.
You also need a bass driver to fill in the bottom end <200Hz and a crossover.
As I was so impressed with the Dragons I had to try the FP-440 Sonic Panel to see if there was a similarity in sound, and the price certainly makes it a very attractive proposition.
To get the system going I used a pair of subwoofers I have in my workshop that use an Acoustic Elegance 18" driver in sealed boxes. The AE drivers are very good, have very clean deep bass but they are also very linear up to 1Khz, which makes them perfect for integrating with the Sonic Panel.
For a crossover I used a DEQX digital crossover- this has the optional Jensen output transformers and is a very nice, analogue type sounding digital active crossover.
I like 12dB 2nd order crossovers for stats and used a 220Hz crossover point.
From a myriad of amps in the workshop the closest was a 100 watt Redgum solid state amp I quite like, so that was connected to the Sonic Panels and a Parasound 200 watter was connected to the bass speakers.
I used the Parasound as it has level controls and I figured the bass level would have to be adjusted down to suit the Sonic Panels 88dB sensitivity. Of course any worthwhile system has to have some tubes in it, so I used a 6SN7/71A DHT preamp to drive the power amps.
It took me no more than 30 minutes to set everything up and have music playing.
First impressions were that this is different: most stats have a rising treble but this panel sounds very smooth , it sounds very much like it's published frequency response- very flat response. The detail/micro-dynamics of electrostatic drivers is still there, but it is not forceful or in your face as much as some stats can be. The Dragons can be a bit too un-restrained sometimes, especially with badly recorded music (they're just being truthful really), but the Sonic Panels are always very enjoyable and easy to listen to.
They dont go as loud as the Dragons, obviously, as they have only less than half the panel area of the Dragons, but still have more than enough output for the average listening room.
Over a period of a week listening to them I've quite enjoyed them, I have them in a very large workshop which is not an ideal listening environment, and this should be borne in mind in context of my impressions, but with JRiver in shuffle mode I've listened to a lot of different music while working on preamps in the early hours of the morning and late at night.
I've often been drawn over to the listening seat to have a closer listen to something that sounded interesting, and always found the sound to be very satisfying- it is not the strident "studio monitor" sound that can sometimes be tiring , but a very natural, musical sound. Quite different from most stats and something that I think is very worthwhile.
Like the Dragons, imaging is very good, they throw a good 3D effect, with excellent width and depth, the crossover has a lot to do with this.
I think they are a real bargain, and recommend them for anyone who would like to try stat sound at a very affordable price.
I'll soon take them into my main listening room , try tube amps, different crossovers, etc, and report on how they go.
Whats next? I'm going to order another pair of panels to double up and see how that sounds. More is better? Maybe, maybe not.
I've also ordered a pair of AE 15" dipole drivers as I want to make a simple frame using a slim open baffle design. It may work with the Sonic Panels and it may not, we shall see.
http://www.aespeakers.com/drivers.php?driver_id=32
http://www.involveaudio.com/audio.php?id=33&pid=10
The speaker evaluation kit contains a pair of panels, a step up transformer and a DC power supply , essentially everything you need for a speaker to work from its lower frequency response of around 200Hz to 20Khz.
You also need a bass driver to fill in the bottom end <200Hz and a crossover.
As I was so impressed with the Dragons I had to try the FP-440 Sonic Panel to see if there was a similarity in sound, and the price certainly makes it a very attractive proposition.
To get the system going I used a pair of subwoofers I have in my workshop that use an Acoustic Elegance 18" driver in sealed boxes. The AE drivers are very good, have very clean deep bass but they are also very linear up to 1Khz, which makes them perfect for integrating with the Sonic Panel.
For a crossover I used a DEQX digital crossover- this has the optional Jensen output transformers and is a very nice, analogue type sounding digital active crossover.
I like 12dB 2nd order crossovers for stats and used a 220Hz crossover point.
From a myriad of amps in the workshop the closest was a 100 watt Redgum solid state amp I quite like, so that was connected to the Sonic Panels and a Parasound 200 watter was connected to the bass speakers.
I used the Parasound as it has level controls and I figured the bass level would have to be adjusted down to suit the Sonic Panels 88dB sensitivity. Of course any worthwhile system has to have some tubes in it, so I used a 6SN7/71A DHT preamp to drive the power amps.
It took me no more than 30 minutes to set everything up and have music playing.
First impressions were that this is different: most stats have a rising treble but this panel sounds very smooth , it sounds very much like it's published frequency response- very flat response. The detail/micro-dynamics of electrostatic drivers is still there, but it is not forceful or in your face as much as some stats can be. The Dragons can be a bit too un-restrained sometimes, especially with badly recorded music (they're just being truthful really), but the Sonic Panels are always very enjoyable and easy to listen to.
They dont go as loud as the Dragons, obviously, as they have only less than half the panel area of the Dragons, but still have more than enough output for the average listening room.
Over a period of a week listening to them I've quite enjoyed them, I have them in a very large workshop which is not an ideal listening environment, and this should be borne in mind in context of my impressions, but with JRiver in shuffle mode I've listened to a lot of different music while working on preamps in the early hours of the morning and late at night.
I've often been drawn over to the listening seat to have a closer listen to something that sounded interesting, and always found the sound to be very satisfying- it is not the strident "studio monitor" sound that can sometimes be tiring , but a very natural, musical sound. Quite different from most stats and something that I think is very worthwhile.
Like the Dragons, imaging is very good, they throw a good 3D effect, with excellent width and depth, the crossover has a lot to do with this.
I think they are a real bargain, and recommend them for anyone who would like to try stat sound at a very affordable price.
I'll soon take them into my main listening room , try tube amps, different crossovers, etc, and report on how they go.
Whats next? I'm going to order another pair of panels to double up and see how that sounds. More is better? Maybe, maybe not.
I've also ordered a pair of AE 15" dipole drivers as I want to make a simple frame using a slim open baffle design. It may work with the Sonic Panels and it may not, we shall see.
http://www.aespeakers.com/drivers.php?driver_id=32
Friday, October 26, 2012
Combined Pre-amp/ Crossover
I guess the main problem is that the device can only be used with a system totally designed for active use, with seperate amps for each speaker driver, and the crossover points set for a particular speaker system.
I normally use a DEQX digital crossover on my two-way active electrostatic speakers and the versatility of the DEQX is quite useful- I have 3 crossover settings, EQ available via remote control, and can change settings on the fly to suit taste and recordings etc.
The DEQX is very transparent and with tube preamp and tube amps designed for the stats the sound is accurate and natural.
But if you crave an all tube system, and know what crossover settings your speakers need, a tube active crossover can give very good results. With a two way system it is quite easy to go up to 24dB fourth order slopes with tubes, combine a very good preamp in the design and have an exceptionally satisfying sound with all tube pre/active amplification.
Kevin Covi did a lot of crossover design work for me in 2006 and I built quite a few preamp/crossover units for those dedicated audiophiles with a passion for tubes.
Another advantage of combining the preamp and crossover is that the unit can be optimised for the range of frequencies each section covers.
In the pre/crossover I'm using now I have 6SN7/6H30 tubes in White Follower configuration driving the bass section. This is optimised to give very deep, tight bass response.
The mid/treble uses a 6SN7/101D (dht) transformer coupled circuit which is optimised for performance from 200Hz. Normally I use a 71A dht for my preamps as it has the best balance for overall sound, but the 101D is maybe the best tube for clarity and is ideal from lower midrange up to high treble.
With this setup and using a bit of EQ via the JRiver player program the sound is perhaps not as precise and accurate as the DEQX but it sounds wonderfully engaging and musical.
On the pix above the middle front tubes are the bass section, and the round 101D tube handles the mid/treble. There is a seperate volume control for the bass which works in combination with the master volume control.
Wednesday, October 17, 2012
Computer Audio Oct 2012
Computer Audio(CA) continues to advance. People who 6 months ago were telling me that it could never be better than CD/SACD are now emphatic that it is the finest reproduction they have heard.
It's interesting to see how the press critics have come around, and how some of them are trying to wipe the egg off their faces without being seen!
There's still some dissention, but it generally comes from flat earthers who like their sound colored and romantic, that is, very unfaithful to the recording.
They usually have bloomy tube amps or colored speakers that are far from accurate.
There's no hope for these people as they don't want to hear the recording, they want to hear their version of how it should sound.
However for those of us who do want to hear the actual recording of the music, it is getting easier and easier to accomplish.
I believe quite a lot of people are keen to dip their toes into CA but are a bit apprehensive about it, believing it is quite difficult and it requires a fair bit of computer skill.
There's no denying a little computer skill helps, but even the average 60 year old has enough experience of computing to manage CA now.
And if you haven't got it, you damn well better get it or you will be severely disadvantaged in the near future.
Basically to use a computer for audio you need 4 things,
(1) a computer or laptop, loaded with windows 7 or 8
(2) a program to play the files, either JRiver for windows or PureMusic for Mac (there are others, but let's keep it simple
(3) a storage system for music files, I strongly recommend a simple USB powered 500Gb portable hard drive . I can carry all my music around in my pocket, it's simple, and as long as you have at least one backup is safe.
(4) a USB dac.
That's it, that's all you need for very high quality sound.
Of course you can make it a lot more complicated, and even higher quality, but this is a great way to get going and my systems are loosely based on this set-up.
There is a bit of potentional angst in setting up the program player, but computer people seem to finally have realized that not everyone is a geek and the programs are a lot more explanatory now, and if you have problems it's not that hard to get help.
I've helped people set up computers for CA in less than 30 minutes , and it's always fun to see the look on their faces when they hear pure digital as it should sound.
If any Supratek owners are contemplating CA and require some advice please feel free to email.
BTW I have a MicroMega MyDac usb dac for sale @ $AUD350, perfect for introduction to CA.
Next blog, back to the future, our version of the ultimate phono preamp.
It's interesting to see how the press critics have come around, and how some of them are trying to wipe the egg off their faces without being seen!
There's still some dissention, but it generally comes from flat earthers who like their sound colored and romantic, that is, very unfaithful to the recording.
They usually have bloomy tube amps or colored speakers that are far from accurate.
There's no hope for these people as they don't want to hear the recording, they want to hear their version of how it should sound.
However for those of us who do want to hear the actual recording of the music, it is getting easier and easier to accomplish.
I believe quite a lot of people are keen to dip their toes into CA but are a bit apprehensive about it, believing it is quite difficult and it requires a fair bit of computer skill.
There's no denying a little computer skill helps, but even the average 60 year old has enough experience of computing to manage CA now.
And if you haven't got it, you damn well better get it or you will be severely disadvantaged in the near future.
Basically to use a computer for audio you need 4 things,
(1) a computer or laptop, loaded with windows 7 or 8
(2) a program to play the files, either JRiver for windows or PureMusic for Mac (there are others, but let's keep it simple
(3) a storage system for music files, I strongly recommend a simple USB powered 500Gb portable hard drive . I can carry all my music around in my pocket, it's simple, and as long as you have at least one backup is safe.
(4) a USB dac.
That's it, that's all you need for very high quality sound.
Of course you can make it a lot more complicated, and even higher quality, but this is a great way to get going and my systems are loosely based on this set-up.
There is a bit of potentional angst in setting up the program player, but computer people seem to finally have realized that not everyone is a geek and the programs are a lot more explanatory now, and if you have problems it's not that hard to get help.
I've helped people set up computers for CA in less than 30 minutes , and it's always fun to see the look on their faces when they hear pure digital as it should sound.
If any Supratek owners are contemplating CA and require some advice please feel free to email.
BTW I have a MicroMega MyDac usb dac for sale @ $AUD350, perfect for introduction to CA.
Next blog, back to the future, our version of the ultimate phono preamp.
Thursday, September 20, 2012
Whise HA1500 aka Nakamichi Dragon
I dont normally do "reviews" as sound is so subjective - we all hear differently and have different priorities towards sound quality, so my opinion of a product is just that- an opinion.
I'm also not impressed with the majority of reviews in the audio world, as most reviewers have an appalling lack of technical knowledge, and are really quite unqualified even to broadcast an opinion.
Never the less, I've come across a product that I would like to make comment on, as the design philosophy is very close to what I consider to be state of the art in audio playback.
Regular readers of this blog will know that my reference speaker system is a hybrid active electrostatic system that consists of a Martin Logan Request , which has a large electrostatic panel with 12" bass driver in sealed box. The bass is driven by a solid state amp and the stat panels are each driven by a strong tube monoblock amplifier.
The passive crossovers are removed, crossover is by DEQX, 12dB Butterworth. Adjustment to sound done via computer USB and can be done on the fly , with levels/EQ able to be adjusted from burning your ears out with detail to warm euphonic "tube" sound.
Of course I prefer a natural, accurate sound.
The system is complex, heavy, burns a lot of watts and sounds very good.
The Whise HA1500 is also an active electrostatic speaker with built in power amps, crossovers and adjustment controls . It is relatively compact, comes in a glorious design and finish , so good that it won a Good Design Award 2007 from the The Chicago Athenaeum: Museum of Architecture and Design .
Normally a speaker with this type of looks and finish would exist in the 10-15$K price range.
The Whise HA1500 has had an interesting history; conceived and designed in Australia, it was presented to Nakamichi of Japan who decided to market the speaker under their brand and gave it the highest distinction by naming it Dragon, which is reserved for the highest echelon of their product range.
The Nakamichi Dragon tape deck is still considered to be one of the finest recording devices ever made.
Unfortunately the relationship between Nakamichi and the designer/manufacturers fell through and only around 200 pairs were built.
They've been available in Australia for a few years, and have been quietly sold through various retail outlets.
I became aware of them a few years ago, and admired them from a distance, and even came close to buying a pair in 2010.
Recently the price became even more attractive as the manufacturers wanted to quit all stock and move onto other projects and I could not resist temptation any longer.
Using the Dragons simply requires an input from a preamp, line source or amplifier terminals, although under the latter method the Dragons inbuilt power amps are still driving the speakers.
I connected a preamp , and watched as the yellow neon lights on front panel turned to blue as audio was detected, very cool, and I sat down with an iPad in my hand to remotely select some music.
The Dragons have a series of controls on the back panel, consisting of volume, and 3 tone controls: a "room brightness" control to adjust treble, a +- 6dB bass control at 80Hz and a +- 6dB control at 250Hz which is approx the crossover frequency.
I placed all controls at the 12 o'clock or midway position and played some music.
Immediately I could tell I was listening to a very good speaker, but the frequency response was not right at all, with too much bass, and too much treble.
It turned out that the 12 o'clock position is not the "flat" position for the controls , and I spent a considerable amount of time adjusting the controls to get a reasonably flat response.
The Dragons are difficult to adjust , I dont know why the designers chose this particular set of controls , but I would have much prefered to see simple level controls for the bass and stat sections of the speaker; the separate sections of the speaker are very good, and don't need such heavy handed controls imo.
I've read of people immediately disliking the Dragons, I'd suggest the tone controls were not set to advantage, it is quite easy to make the dragons sound very strange with the tone controls.
However, they do provide the means to adjust the sound to suit a wide variety of rooms and taste, it is a slow and tedious procedure but after a couple of days I was quite happy with the frequency response. Later on I moved them into a quite different and larger room and had to go through the same procedure, but again had good success at integrating them into the room.
If achieving the correct frequency response was hard work, there was certainly no problem in recognizing that the sound of the electrostatic Dragons was extra-ordinary. The music literally leaps out of the speakers in a highly defined soundstage that has excellent width and very defined depth, perhaps the best 3D effect I've heard . Detail is amazing , electrostatics are renowned for resolution, but the light membranes used in the Dragons give the best resolution and transperancy I've heard from the dozen or so electrostatics I've heard over the last 40 years. They are very, very fast, I doubt there is a speaker available that has the rise time of this electrostatic panel.
But they aren't overly bright or fatiquing - the "room brightness" control needs to be adjusted accordingly to avoid treble attenuation, but used appropriately the speakers give a very natural, organic sound.
The amazing transperancy does mean that a very good preamplifier needs to be used, I went through 5 preamps before I found one that I thought really suited the speaker and my taste.
Some will use the speaker with a direct connection to a line source, this may work well, but I'd always use a tube preamp with an active set up, or indeed any serious audio.
The ultra-quality of the sound exposes any weakness of equipment and recordings, other owners of the Dragons say the Dragons are best with certain equipment and recordings, that some recordings don't suit the Dragons.
I think it is a case of the Dragons revealing the short-comings of these recordings, a less than optimum recording may escape observation by lesser speakers, but the Dragons reveal all.
The bass of the Dragons is particulary interesting.
Now I'm not usually impressed or believing of the marketing hype that comes with audio products , but there are some aspects of the Dragon design that are innovative and clearly audible and to quote the Dragon literature:
” Balanced PAMSubwoofer technology for a powerful bass experience without any loss of punch or transparency in the low frequencies;
” Ultra-thin Electrostatic Loudspeaker (ESL) Arrays which break boundaries in physical size, dispersion, loudness (SPL) and transparency, to provide a musical experience with unsurpassed realism.
” Ultra-thin Electrostatic Loudspeaker (ESL) Arrays which break boundaries in physical size, dispersion, loudness (SPL) and transparency, to provide a musical experience with unsurpassed realism.
The advanced subwoofer technology adopts advanced acoustic measures to ensure that the bass/sub bass audio is clear from distortion and vibration. Harmonic distortion is reduced to incredibly low levels, even at full power, combined with an incredibly fast transient response"
Whise were highly regarded in the pro-audio world, and their sub-woofer technology has filtered down into the Dragons. Neither of the 2x 8" drivers are visible as they are used in a band-pass design which encloses them inside the enclosure. Output is from a single port, and frankly the definition and output from this port is hardly believable.
Those damn tone controls have to be used again to get the output reasonably flat, but once done the bass is as clean and free of overtones as you could hope for from such a reasonable sized enclosure.
Whise called this form of bass modelling P.A.M and Greg Borrowman in a review of a Whise subwoofer explained very well how it works:
A very good test of a subwoofer is to drive it with a full-range audio signal and listen to what comes out. The easiest way of doing this is to connect the line output of a CD player to the line inputs of the sub, insert a CD and press ‘play’. What you shouldn’t hear are any muffled higher-frequency sounds, particularly voices. Try this test with the Whatmough-Whise Impulse and all you hear are low frequencies…and if there are no low-frequency sounds on the CD, total and complete silence. The high-pass filtering is that good.
The bass I heard from the Impulse was immediately noticeable because it was so free from distortion that I was able to immediately detect the pitch of every note the instant it was played. In a perfect world, this is exactly what should happen, but the fact is that almost all subwoofers have such high levels of distortion that this is not possible. The mechanism that’s at work is that when a bass guitarist plays a low ‘G’, for example (49Hz), nearly all subwoofers will generate not only this ‘G’, but also another ‘G’ an octave above (at 98Hz, which is the second harmonic) as well as a ‘D’ five notes above that (at 147Hz, which is the third harmonic). So instead of hearing just the one single note, you’ll hear three notes, and it’s up to you to decide which one the composer (and musician) intended you to hear! The ear works this out automatically from the context of the music (the key the music is in lets you eliminate the false D fairly quickly while the phrasing would be the only clue to which G to choose). These decisions are made by your subconscious, in just a few moments, but the more distorted the signal (and thus the harder your ears and brain will have to work) the less ‘easy to live with’ you’ll find the quality of the bass.
Play a ‘G’ through the Impulse and all you’ll hear is the original ‘G’ at 49Hz. The difference this makes to the clarity of music being played is so unbelievable that you really have to hear it for yourself to believe it. When you do, you’ll discover it’s easiest to hear with musical examples, either from a CD or a DVD soundtrack, but the freedom from distortion is clearly audible even with movie sound effects.
The frequency response is exceptionally flat. I connected a standard synthesiser directly to the line inputs of the Impulse and played a two-octave chromatic scale starting at the lowest note on the synth (a ‘B’ at 30.87Hz) I couldn’t detect any change in volume level until I reached the ‘G’ at 98Hz. Needless to say, if the Impulse can pass such an extreme ‘live music’ test, you’ll have no worries playing back recorded music. The synth also showed the Impulse’s response dropped off very quickly above the ‘G’, being noticeably softer even just three notes above, at ‘C’ (130.81Hz). The Dragons also have this character of low distortion, but that very steep roll-off of the higher harmonics is particulary evident , and leaves the splendidly clean and resolving sound of the stat panel free of any bass overtones or "muddiness.
Bass is similarly transperant and resolving- there is never any "one note" tone and one can easily follow a bass line quite distinctly from the music.
The two technologies of PAM bass loading and the light weight, high speed electrostatic panel combine perfectly , although this is an active hybrid system, it is integrated in superb unison.
One downside is that the downward extension of bandpass designs are restricted by enclosure size. The Dragon has exceptional bass, but it does not do sub-bass, you need a real sub-woofer to get earthquake effects. Again that 80Hz tone control is of no help here, its just too high for sub-bass control.
Another of the marketing claims is for what is called NTM crossover design.
The Dragons use an analog crossover which surprisingly uses quite ancient IC chips, however they have been proven as high quality sound devices over a long period- think of them as NOS exotica!
The design is claimed to offer high order roll-offs with low order group delay, and it certainly sounds like this to me.
I've had a lot of experience with active crossovers and while it is possible to get very high order crossovers these days, they never seem to have the same "organic-ness" and natural sound of lower order crossovers.
The designers of the Dragon claim to have combined the best of high and low order crossovers and I believe them. The proof is in the splendid 3D imaging and sound-staging that extends beyond the physical boundaries of the speaker.
Internal amplification is by 100 watt class AB amps, one each for the stat panel and the dual bass drivers. They sound fine, there's no mistaking they are solid state amps, but they have good tone and good control over the drivers.
Without passive crossovers to soak up the power the Dragons can play very loud- at extreme volume levels they do strain a little, but this is at volume levels you only get to enjoy when home alone.
Once upon a time stats didn't do high volume, but the new designs available now are up there with the very best at providing clean volume, the Dragons are probably better than the majority of moving coil speakers for loud, clean and accurate sound.
So how does the Nakamichi Dragon compare to my similar Martin Logan active stats?
Firstly, my ML's are heavily modified and quite different to a stock Martin Logan Request, I dont think there is any comparism to a stock ML and the Dragons- the Dragons are clearly better in just about every way. My modified, active Martin Logans are quite a bit larger than the Dragons and do have a slightly bigger soundstage, but the stat panel technology of the Dragons, combined with the special crossover gives better imaging - that 3D presentation I keep talking about, the Dragons also have more detail and insight.
The Martin Logans have a baffle mounted 12" bass driver in a sealed box; while not as well defined as the Dragon bass in the upper bass region, it does extend further into sub bass area and moves more air than the rear mounted port of the Dragon can.
The big advantage the Martin Logans have is that external amplifiers are used, and they are powerful 100 watt tube amplifiers especially built for stats.
As good as the Dragon stat/class AB amp combination is, nothing sounds as real as a stat driven by a capable tube amp.
The ML's may lose a little detail in comparism, but they are smooth and very naturally musical.
Musical sessions are enhanced and prolonged by this rare ability to connect with the music.
I really enjoy the Dragons but after a while you realize you are listening to a very good speaker without perhaps the involvement the active tube driven ML's give.
The ML's also have the advantage of a very useful and very variable digital crossover, the DEQX can offer an option of 3 crossovers available on the fly, EQ which is very useful for extending and tightening bass well into the sub-bass area, and tuning for room effects/ taste.
But this comes at the cost of complexity and less than eco-friendly power requirements, 4 amps, DEQX, preamp, and line source. And most people don't have the ability or inclination to do a modification of this scale.
The Dragons simply need a line source, although I consider a preamp a neccessity. As a complete package the Dragons are awesome, and I consider them to be possibly the best audio product to ever come out of Australia.
If they didn't have those damn tone controls and had the ability for the stat panels be driven by a tube amp I would consider them the perfect speaker.
Hopefully the designers will one day resurrect the concept, in the meantime I'm happy to join 200 other owners in enjoying the music.
NB I'm using the Dragons with JBL active subs, and a little bit of JRiver 64 bit EQ.
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