Lipinski L707 speaker . Studio Monitor quality. Very highly regarded, used in studios all over the world . Comes with 15" subwoofer (one cone with rubbing voice coil)
UPDATE JAN 2026
So what is happening with Supratek ?
In 2023 I was diagnosed with neuroendocrine cancer - Grade 3, Stage 4 . Metastasised to liver and bones , so, at the moment uncurable .
I underwent some pretty serious chemotherapy and radionuclide therapy and am now stable for the moment.
I'm feeling quite good, but have retired .
I'm trying to get the last orders for preamps done, and am still available for repairs in Australia and Asia.
Johhny Slate in North Carolina can be contacted at supratekrepairusa@gmail.com for repairs and all things Supratek in the US.
I'm enjoying life , listening to music , keeping fit and building the occasional piece of audio equipment to keep my hands and mind active.
After nearly 50 years of audiophile nonsense, I have quite a collection of audio equipment and parts.
Amplifiers, speakers, speaker drivers, preamps, transformers( power, output and interstage), components etc. Thousands of audio tubes.
Too much and I want to clear my workshop of most of it.
I'll soon begin to list it all on this blog , so keep an eye on this page .
It will all be at bargain prices - I've had some of these goodies for a long time and I'm not aiming to make a profit on it, so prices will be bargain basement - NOS tubes for $10 etc.
Give me a good reason and I'll give it away!
Please don't contact me before the lists go up, it's a big job and I probably won't reply while I'm doing it.
Pix below of my end of game system - well that is what I tell myself, but it does sound great and I'm grateful for the time I have listening to it.
At the heart of system is the Grange preamp .
Bass amp is one of Bob Carvers Load Invariant amps - I'm using a T-Bass device which basically gives sub woofer extension to a conventional bass driver in Open Baffe configuration. But its a 1-2 ohm load so need to use a solid state amp to get the necessary voltage - The Carvers can do that while sounding like a big powerful tube amp.
The mid or full range amp is one of many I use depending on my mood or the season. Single ended 6C33C-B , 300B, 6B4G or 6B4G , EL34 push pull amps.
The tweeter amp is a Loftin White 6B4G (my favorite tube) Single ended amp .
FOR SALE
I've an Ebay Store (Supratek) on which I will list items under these categories:
Tubes/Valves
Speakers/Drivers https://supratekaudio.blogspot.com/2025/12/speakersdrivers-for-sale.html
Preamplifiers
Turntable/Accessories
Amplifiers
Tube Audio Books
Transformers
And more as I uncover items. Rock Bottom Bargain Prices . Make me an offer.
Ok Lets start the list with tubes I have available for sale .
Minimum order is $AUD100 . Its not worth my time for less after testing and close matching for emmission , packaging and sorting etc.
Contact me with what you want and we'll sort it out.
POWER TUBES
6G6G
6F6
EL32
7027A
6V6
EL34
EL37
6336
6AS7/6080
S12E1
S11E12
807
6K6G
6Y6G
DHT PREAMP TUBES
33
101
4P1L
6P2L
3A/110A
19
30
26
71A
DHT POWER TUBES
805
211
6B4G
801A/10/10Y
CV1076/DA42
830B
809
300B
OCTAL PREAMP
6J5
6H9C/6SL7
6SN7
6F8G
5 PIN PREAMP
37
76
56
RECTIFIERS
CV187
8020
3B28
VOLTAGE REGULATORS
OA2
OA3
9/7 PIN PREAMP TUBES
12B4A
6E6P 6E5P
6H23
5693
12AU7
6C19
5965
SV83
12AX7
6N2C
12BH7
12AY7
6J6
12AT7
6BQ7
6CM7
6GK5
6N1P
6AL5
417/5842
EF86/6267
6C4
6CB6A
6CW5
6211
6CW7
6BM8
6CG7
6U8A
6072
e180F
E810F
ECC88/6922/E88CC
5687
and more .....
During the course of my 40+ years of audio (5 years to get to 50!) I've designed and built many hundreds and hundreds of preamps, power amps, speakers etc .
Of these, the prototypes were very exotic and dedicated designs , using all sorts of vintage and modern components , with design elements coming from the early 1900's up to the present day state of the art.
The amplifiers and preamplifiers I've released as commercial offerings have to offer great sound, but also have to be very reliable , and use parts and components that are, and will be available now and into the future. And I've always believed in a fair and realistic price , value for money , not the ridiculous prices many relatively inexperienced manufacturers hoodwink customers into paying.
But I've always enjoyed pushing the limits with design and building - sometimes just to see what will, and wont work in the quest for sonic nirvana.
90% of these never get public attention - I'm somewhat of a "lone wolf" in audio, partly because of where I live ( the most isolated state in the world - and we like that just fine) and I mostly do this for myself, I'm not that interested in forums and handclaps.
But recently going through my files of circuit designs I realised just how many interesting designs I had stored over the years.
Tube audio design seems to have stagnated a little over the last decade - I guess we're almost at the summit , and there's little that hasn't been investigated and tried.
Early on in my audio career I was obsessed with finding the "best" amplifier or the best preamplifier and doggedly built device after device trying to find that holy grail.
After many years I came to the conclusion that there is no "best" . The ultimate goal is to find the sound that suits your ears, a sound that comes together with the synergy of all your components -sources , amps and speakers (and importantly room) that brings you satisfaction and joy .
Enjoying the music - that's what it's all about eventually , and you dont need the "best" equipment or the most expensive equipment to get there.
In that spirit I'd like to present some circuit designs that I have built and enjoyed, and even some designs that maybe didnt quite work out, but were interesting and were part of the journey.
This is mainly for the more technically minded audioholics , not everyone can make sense of a badly drawn circuit diagram, but maybe a little of the zen of tube audio design will come through.
I'll put up photos if I can of the completed amps .
This will be ongoing and will eventually be a very long page, so keep checking back if you are so inclined.
Incidently , I have thousands of audio tubes , transformers and components collected over my long audio career.
I'll be putting up a list of these soon , for sale , at very reasonable prices - I've had them for a very long time , and wont charge the ridiculous prices some vendors are seeking these days.
Email if there is something your after, and no I dont want to sell any 300B, 45 or 2A3 tubes, but I do have many other fine audio tubes.
The 6C33C-B tube and the Supratek Merlot SE amp.
The 6C33C-b tube is perhaps one of the finest audio tubes ever released , although it was never designed for audio- it was used in the power supplies of Russian fighter jet electronics.
With a plate resistance of around 100 ohms , many times lower than any other triode , its relatively easy to design and build a suitable output transformer with very good bandwidth - its possible to easily get 10hz to 100Khz flat response , and I've built OTL 6C33C-B amps that got to 250Khz easily.
But with that response comes very low output impedance , so that response can be transferred into a complimentary speaker with little or no feedback.
A good 6C33C-B SE (single ended) will be very transparent and detailed with high clarity . They are often described as being powerful sounding , for the power they produce , around 18 watts , but also with an elegance that is unique in audio amps.
They have drawbacks though- they produce a lot of heat , they need substantial power supplies, and they can vary quite a lot from tube to tube, which makes biasing them a bit of a chore, although there are ways around that.
Tube curves- vey linear .
Supratek Merlot . I started building these in the late 1990's and turn of the century .
The first ones used 6SN7 or variants (76 ,6J5 etc) driving a 300B , which drove the 6C33C-b through an interstage transformer , in either grid or cathode drive. All the Merlots had a second 6C33C-b acting as a regulator for the power 6C33C-b tube.
I built some using Plitron toroidial interstages and output transformers- these were fantastic transformers, and sadly no longer available - I'd love to get a pair of these amps back, they would be prohibitively expensive to build these days .
Back then I also used transformers from Bob Lancroft in Sydney and Sowter from the UK.
Later on I switched to using 6SN7 SRPP circuit to drive the 6C33C-B . The SRPP driver isnt so fashionable these days , but its still a very capable and good sounding driver stage.
These versions had an even clearer and more defined sound , without the 300B DHT euphonics.
Here's an interesting design from Bob Lancroft - it's an interesting direct coupled drive stage .
This is a ideal circuit, no capacitors in the signal amplfication , but it would be a nightmare keeping it running consistently with the varying plate voltages , especially as tubes were changed or aged.
Very courageous and innovative design though - I like it!
I then went on the build the high power and push pull Burgundy and Mondeuse monobloc amps . Also very heavy monster amps . Most had adjustable negative and positive feedback- they could be fine-tuned to drive just about any speaker.
I will try to get some circuits of the push pull amps up onto the blog.
One of the last Merlots I kept for myself , with quite a lot of mods I called it the Super Merlot , and I still use it often. 6EM7 input tube, 10Y driver into 6C33C-B with a custom Sowter output transformer.
It solved the biasing problem with the 6C33C-b as it used a servo that sensed the current through tube and adjusted for individual tubes and as the tube aged.
( Its very handy to use a combination of fixed and cathode bias in 6C33C-b SE amps as it results in a more stable bias. 100R on the cathode )
The Super Merlot is here somewhere on the blog , I'll try to find the link.