Its been a while since my last post- things seem to be returning to some sort of normalcy, so hopefully I'll be able to contribute a few more blogs...
I'd like to talk about my Grange preamp - I used to make the Grange around 15 years ago, just before I took a 5 year diversion from the audio industry ( although I did make the occasional preamp and did a lot of preamp R&D during that time)
The Grange was my piece de resistance and was definitely one of the best looking pieces of audio gear available then, and of course it sounded even better than it looked.
Here's some pix of the various finishes.
The Grange used DHT tubes 300B or 45, much like the DHT Cabernets I build today - a different circuit but the same concept .
I've reintroduced the Grange , once again its my finest preamp and it is available in a number of configurations , starting with :
The GRANGE SIGNATURE
I've never called one of my preamps a signature model , but this Grange is definitely my baby .
It's circuit is what I personally find the most satisfying and engaging to listen to. Its a circuit that draws you in to the music , not in a "hifi" or overly analytical way, but really gets to the heart and soul of the recording. Its the type of preamp where you sit down to listen to a song and an hour later your still there.
It uses NOS (New Old Stock) tubes that I have personally kept over many years for my own personal use . The line stage uses 6J5GT tubes which is an early version of a 6SN7 but has a single plate instead of the dual plate 6SN7.
I have a big box full of NOS 1944 Kenrad 6J5GT , enough for many Signatures and spares. The 6J5 is also easier to source these days than the popular 6SN7.
There are some very good 6SN7's being made these days - they are very accurate and well balanced, but there is a certain type of magic about the old NOS tubes that just doesn't come across from the new production tubes . They are "warmer" but also have a bigger picture - they sound less forced and very natural. Which is why the best NOS 6SN7's are so expensive and hard to find now.
Being a single plate I'm using 4 of 6J5GT in the line-stage rather than the 2 6SN7 I usually use.
The phono stage of the Grange is also very special- again it uses NOS tubes that I've kept especially for the ultimate LCR moving coil tube phono .
It uses SQ (special quality) E180F manufactured in Britain , Russian military 6E6P amd American cyro treated 12B4A tubes. All from towards the end of the Golden Age of tube technology before transistors became the dominant technology, because of their economic advantages.
(I'm tempted to say transistors took us into the Dark Ages of Audio , but that's maybe a bit too far)
Of course the Grange phono is a LCR circuit which uses expensive Lundahl inductors which are especially made for me .
LCR phonos have a sound that is very engaging and pleasing to listen to- very natural and musical sound, but also very transperant and revealing.
So the Grange Signature is a line stage with adjustable gain 0-16dB and a MC capable phono stage suitable for the very best cartridges with outputs of 0.1 mV to 0.4mV .
From the Left: Impedance Selector for MC cartridge. 2x MC cartridge RCA connectors. 1x XLR input.
3x RCA inputs. 3x RCA outputs . 2x XLR outputs . Power Supply Connector.
The power supply has separate tube shunt regulators for both linestage and phono L&R channels - so four 6P3S (6L6GC) tubes plus a pair of 5AR4 rectifier tubes.
Now we move on to the DHT Grange .
This very similar to the original Grange , but uses a newer circuit developed based on a similar concept as the current Supratek DHT Cabernet.
However the Grange DHT uses special output transformers especially made for Supratek by Lundahl in Sweden .
It can use 300B, 45 or PX4 DHT tubes and uses a 6SN7 driver tube .
DHT tubes have a warmer , euphonic sound that is appealing to many people , and can be very transformative with some systems , especially with a system that is perhaps a little too "hi-fi" and needs a touch of magical tube sound.
However, the Grange DHT circuit is technically advanced and has a state of the art performance with flat and extended frequency response
I've been told the DHT Suprateks have an amazing synergy with Magico and Wilson Watt speakers.
The phono stage of the DHT Grange is exactly the same as in the Grange Signature.
The DHT Grange can also be configured as the Grange DHT/6SN7 , which in addition to the DHT line stage has an additional 6SN7 output line stage , with the same gain as the DHT section.
Not sure if you want a DHT(Directly Heated Triode) or IDHT (Indirectly Heated Triode) - you can have both!
This also enables bi-amping with speakers that can be configured to have seperate amps for bass and mid/treble.
I've been a fan of active speaker operation for many years .
My 5 way horn system has 5 channels of amplification and a custom preamp that has 5 stereo outputs- 1 for every power amp to enable very precise adjustment of speaker driver levels. You could say its way over the top and it probably is, but it sounds great!
My Open Baffle system is a three way -bass , mid and treble drivers and it has a seperate power amp for each driver - 6 monobloc tube amps and they are driven by a 6SN7 Cabernet that has 3 sets of stereo output sockets . Each power amp has its own level adjustment to set driver levels.
Both of these systems are perhaps unrealistic for the average domestic home , but my third system is more representative of a domestic active speaker system.
Its an orthodox box speaker that has a jumper between the bass and mid/treble cable connectors on back of speaker. If the jumper is kept in place a stereo amplifier drives the bass and treble drivers. If the jumper is removed then seperate amplifiers can be used to drive the bass and mid/treble drivers.
Its quite common and many speakers have dual connectors.
The DHT/6SN7 Grange can be used in such systems - typically the DHT section would drive the mid/treble amp and the 6SN7 would drive the bass, or perhaps even the other way around.
However, to maintain the speaker designers intention , you would have to use two sets of amplifiers with equal gain , otherwise the tone would be tilted either towards the bass or mid/treble.
The speaker designers intention for frequency response of the speaker might not necessarily be the best sound for your room and taste. Perhaps a slight shift in bass or mid treble might make a significant difference to the sound quality in your room.
As I said, I've been a big believer in active amplification for many years, and I'm happy to see it becoming more common these days.
The DHT/6SN7 Grange , the DHT Grange and the Grange Signature (with 6SN7 tubes) can be configured with level controls for both linestage outputs. This enables very precise adjustment of both bass and mid/treble outputs in order to get the very best out of an active system.
The Grange is the very best preamp I can build. Its large and expensive and the best preamp you can buy.
