Preamp Deal of the Century

Hi Fiddler, try Herbies iso-cups instead of the cones. Should improve things even more.

Hi Fiddler - agree totaly with your results - I actually added a hardwood base under the metal bottom plate just using longer screws ( and drilling vent holes) so I could use footers of various types - only difference is I have found that balls work better than cones ( I did a diy roller ball type using ceramic balls)

It is amazing how these things make such a difference - hard to explain the tower of stuff under your amp to visitors tho

cheers

I have been auditioning new interconnects and in the process I was forced to move my Chardonnay due to differing IC lengths which forced me into a new quest for isolation for my preamp.

What a fortunate turn of events. I previously had my Chardonnay on DH Labs ceramic cones, points down, sitting on a Neuance platform. I have been fighting an upper mid-range glare that I suspected was coming from my Berning ZH270 amp. Frankly, I didn't suspect that my Supratek was the culprit.

On my Chardonnay, I had the DH Labs cones attached to the underside of my chassis with two cones mounted beside the screws where the original feet were installed and one cone in center-rear of the chassis. Initially, I removed the Neuance and replaced it with a Lexan shelf supported four Herbies Tenderfeet, one under each corner of the Lexan. I placed my Chardonnay back into the system and the imaging immediately became much tighter by removing the Neuance shelf.

I then decided to cut another 1/2" thick Lexan shelf and I placed it on top of a piece of bubble wrap, sandwiching the bubble wrap between the two sheets of Lexan. Wow, much more clarity and better imaging still. The mid-range glare was still present so I decided to move the cones in front of the unit out to the very edges of my preamp underneath the wooden frame of the unit. Much better yet.

On a lark I decided to turn the front DH Labs points ups beneath the wooden frame and now things really popped into place. Midrange glare still present, but the imaging and clarity were magnitudes better. I then moved the center-rear DH cone to one rear rail, adding a fourth cone to the other rear rail, making it one cone under each corner of the wooden frame. What I immediately concluded was the metal plate on the bottom on the preamp was a source of fuzzy imaging (which escaped me before) and also the source of the slight upper mid-range glare in my system.

I have concluded that using the bottom plate for support with either the stock feet or with cones is a major mistake in my system. I did find however that using cones under the four corners of the wooden frame imparted a very analytical quality that became too much of a good thing. I subsequently replaced one cone beneath the rear-center of my preamp; point up on the very rear edge of the unit with a Herbies Big Fat Dot between the tip of the cone and the plate on the bottom of the preamp. This brought the warmth back to the music without losing any of the clarity and focus. It was a home run solution in my system.

I will spare you all of the experiments in between with maple blocks, metal cones, damping materials, etc. that I tried in between the "home run" recipe and my initial Neuance setup. In the end, anything added or subtracted to my home run recipe was a step backwards.

Incredible clarity, separation of massed violins, separation of voices, even more holographic imaging and a more expansive soundstage in all directions are the results of my experiment. If you are like me and are constantly looking for that bell-like clarity without the often associated sterility, I would highly recommend experimenting with getting your Supratek off of the stock feet or any other type of foot that rests on the bottom plate of the unit. Try the edges of the wooden frame for isolation and see if you get similar results. I can't believe the sheer amount of information I am hearing now compared to before.

I do realize from earlier posts in this thread that some like the more romantic, diffuse sound of the stock Supratek unit. (Not me - I installed V-Caps and a DACT attenuator which removed a great deal of the diffuse imaging and haze in my unit.) So, if you are happy with the way your Supratek sounds, leave my isolation ideas in the dustbin of history. If however, you feel like experimenting, I hope you enjoy similar results in the end. I do have some Sorbothane coming from McMaster Carr that I am going to substitute for the bubble wrap as an experiment. After reading the Sorbothane website and their design "guide", I realize that I have used the wrong implementation of Sorbothane in the past. If anyone has any further interest in the Sorbothane results, I will post them here.

(To make it easier to follow my final recipe, I will recap it here for simplicity.)

On top of my Salamander Synergy cabinet is:

four Herbies Tenderfeet, followed by-

a 1/2" Lexan shelf, followed by-

a sheet of bubble wrap, followed by-

another 1/2" Lexan shelf, followed by-

two DH Labs Cones, points up beneath the very front corners of the wooden frame of the preamp and one DH Labs cone, point up, in the center of the back of the unit on the very edge of the metal frame/plate. Between the point of the cone and the bottom of the metal plate is a Herbies Big Fat Dot

(By the way, I have all of my components on a Lexan shelf now with Herbies Tenderfeet beneath the four corners and Lexan has given me the best results yet of any isolation material I have tried. My other components did not respond to the *additional* isolation tweaks of my “home run” recipe like the Supratek did.

CCS update:

I installed the cascoded CCS in my Chenin and experimented to find the best settings. I have found that 15mA plate current sounds optimal, with 3.45V cathode bias. Incredibly clean, clear and lifelike. Plate voltage is ~175V at idle.

Hi Kgturner, Mick just responded - pin 2 is hot.

chevlam:

i can't recall which is the hot for the balanced outputs, but you should be emailing mick for some of these questions. i've emailed him twice already with some basic questions regarding tube compatibilities and he's always responded in less than 24 hours. hopefully somebody else can chime in and help, but mick can tell you just as quickly.

Can someone tell me which pin is hot for Chardonnay balanced output?

Thanks

Young, Mick did indicate he will be making only one or two grange per year from now one. Sad. And what you think of the sound. I am still not sure of the best position with the gain control. Hope your are having better luck. And please email me the manual. Thanks a lot.

I had a chat with Mick when he dropped off my Chenin. He said that he's not back in business, but is making the odd preamp with remaining stock to 'keep his hand in the game'.

I contacted him at a time when he was just finishing off a Chenin, so got lucky.

You can still contact him, but you'll have to ask if he's willing to make one. He indicated that his building preference was for the higher level preamps.

Hi Chevlam,

Mick dropped off my new Chenin on Monday when he came up to Perth.

He emailed me the manual last night, so I'll send it to you.

I didn't follow the thread since December (a busy year...) and I am surprised about the comments on Mick's support of his loyal customers. I own a Chenin since 2005 and a pair of Malbecs since 2007. I had a small problem with the Chenin that Mick solved in a day with my audio engineer here in Philly. That was fast! I didn't have any problem with my Malbecs. I am still in contact with Mick, but regarding our other shared interest: good wine! I was the person that suggested the name "Malbec" for these amps, because malbec is the best wine that my native country, Argentina, produces. I ask him, now and then, about audio stuff and he always answers it promtly. I love my Suprateks and I am constantly comparing them with good pres and amps and they still are in my system. Next week I'll get an Allnic H 1500 and I compare it with the Chenin. Let's see what happens! Pablo.

The increased gain comes from the constant current supply (CCS) on the 2C22 tube plate. It allows the tube to operate at maximum efficiency by ensuring a constant current regardless of load - CCS is very popular with the tube DIY crowd, and now I know why! The preamp seems to have unlimited supplies of clean power with the CCS, and vocals are downright startling.

Since I substituted the single triode 2C22 for the dual triode 6SN7, I had much less gain than stock, so I don't have the "too much gain" issue anymore.

Ait, thanks for the input. BTW,you put more gain?! I am having problem to determine the best gain position because it is simply overwhelming in my system. Now, I am settled with the gain at tube set to middle and at the back 2 steps down.

But that not final because at different loudness the rear gain switch gives better sound at different position.

One thing that I can say is that Chardonnay may sound bright but on the other hand the preamp meant to be listened at realistic live level volume then it is the best sound I have ever heard.

If you want to play soft music then I suggest Chardonnay may not be the right choice because below the realistic live performance loudness it sounds bit uneven with highs emphasized. It is meant for real music as live music intended((not very loud though)) maybe around 80db on your SPL.

Just my thought after 50 hours of burn in.

ST

p.s. Is there any new owners of Supratek?

Correction, the last paragraph above should read "diode bias" not "diode bypass".

Further Chenin Tweaking (7193/2C22)

Well, I took the next step and replaced the plate resistor of the 2C22 tube with a constant current source, using an IXYS IXCP10M45S current regulator chip. A resistor in series with the chip adjusts it to whatever current you need. I'm running at 11mA current, with 3.45V of cathode bias (4 Cree SiC Schottky diodes replacing the cathode resistor and capacitor) and ~150V on the plate. The sound is incredible - this is the best my system has ever sounded!

A CCS gives you a horizontal load line, meaning very little distortion and maximum gain. It is unbelievable how real the music sounds now, even with the simplest possible CCS.

Next step is to try a more complex CCS using cascoded IXYS chips - the word is that the more complex CCS sounds even better, but that's hard for me to imagine.

Just thought I'd give a heads up to anyone who has done or plans to do the 7193 mod. Adding the diode bypass and CCS is easier than doing the adapters, and the payback is HUGE.

Mick marks them left and right becuase that'sd where they were when he tweaked the adjuustments. He has told me it is not important to keep them that way since the channels are very close.
The Chard is self-biasing using a cathode resistor and capacitor, so there is no need to adjust bias with different tubes.
I have been deep inside my Chenin and done a lot of mods, but I have not completely traced out the schematic (the Chenin has an added layer of complexity because it includes a phono stage). Don't know where you can get one, either.

To all Chardonnay owners,

Can any of you guys help me out here?

1) Why are the tubes marked left and right? And how do I buy left and right tubes? Matched tubes mean it doesn't matter whether it is fixed on the right or left, correct? So why mine came with instruction that 1 pair goes to the left/right and marked accordingly?

2) Do I have to do some sort of internal adjustment for gain/bias when I change tubes to match left and right channel?

3)Anyone out there managed to trace out the circuit? Or managed to identify all important components? I am worried that in long run I won't able to do any repairs if necessary. In my country good technicians are rare breed.

Thanks in advance.

ST

Thanks Kgturner!

I will let my officemate send his inquiries to that email address then.

regards,

Abe

amandarae:

he still responds to supra@supratek.biz.

What email address did you use to get hold of Mick?

Thanks in advance!

Well.... he took my order and in fact he asked me how many do I want?

Chelvam,

So Mick still take orders for preamps?

My officemate, after borrowing my preamp for a week, wants to buy it but I am not selling. If Mick still take orders, I can tell my friend to email him directly then.

regards,

Abe

Update on my 7193/2C22 Chenin Modification:

First of all, let me say I'm reporting on an August 2006 build Supratek Chenin preamp. I was bored with the 6SN7 sound, so I had previously modded it to run 2C22 tubes as single triodes in place of the 6SN7 as a directly coupled triode pair (which is the stock setup). This modification was detailed in this thread, several pages back. I did this by fabricating adapters for the tube sockets, so the 2C22 was still running at the set points for the 1st 1/2 6SN7, namely 100V plate and -3V grid bias (cathode resistor and 330uF cap). I much preferred the sound of the 2C22, so I decided to do further mods to bring the plate voltage up to a more typical range for a single 2C22 triode.

After reading about LED biasing as a replacement for cathode biasing with a resistor and cap (which the Chenin uses), I decided to try it while I was in there. Instead of using LEDs, however, I had some 600V, 1A Cree Silicon Carbide (SiC) Schottky diodes lying around so I investigated those further and found out that their properties were favorable for use as cathode bias diodes. They have a much higher forward voltage (Vf) than a Si Schottky Diode and a very low dynamic resistance, meaning they don't need to be bypassed with an electrolytic cap. The stock Chenin setup uses a resistor bypassed with an electrolytic cap to set the cathode bias voltage.

Since the Vf of the Schottkys was around .85V for the current I wanted, and I needed 2.5-3V of bias voltage, I used 3 of them in series. Since they are in a TO-220 package, it was very easy to stack them and secure them together with a drop of Crazy Glue between each of them - they ain't comin' apart! I then soldered together the appropriate leads and I had a nice neat package. Out came the cathode resistor and bypass cap, in went the diodes. Note: when stacking these diodes together, be aware that the heat sink is connected to the ground leg, so be careful of shorting things out.

I then disconnected the stock 66K plate resistors and wired in 35K pots for each channel so I could easily vary the plate voltage while playing music. I set it at 15K for starters - the plate curves say I should get about 135V at that resistance. I hooked up the power supply and made some measurements:

Voltage to the regulator tubes: was 292V, should be 300V, so I tweaked the adjustment pots behind the regulator tubes up to 300.0V. The difference was most likely due to my use of a GZ33 rectifier instead of the stock 5AR4; that is now compensated for.

RCA 2C22 tubes: one had 133.5V on the plate, the other 145V. The tubes were obviously unmatched! That could be a problem with my new fixed bias, so I went through my 2C22 box and found a match for the lower tube, now they are 133.9 and 133.5 plate volts.

Cathode Bias: was 2.60V dead on for both sides! Those Cree diodes are VERY consistent!

I then hooked it all back up in my system and did some listening. The first thing I noticed was the bass - more yes, but also much more nuanced. The bass lines on familiar songs were there, but I realized that what I once thought was one note was really 2 or 3 notes! Excellent! I think the substitution of the diodes for the resistor and cap was the reason for this improvement, since it was consistent at whatever plate voltage I dialed in.

The other big difference was in the midrange; it was much more meaty than before - I think that was due to the tubes operating at higher voltage and current - they were a bit starved before. This effect was more noticable at lower plate resistor values. I tried everything from 35K down to 10K ohms, and I think I prefer 15K the best. That also happens to place the load line in the most linear region of the plate curves - no coincidence, I guess. Everything just seemed to come together there. I will re-check it all tomorrow, and if I get the same result, I'll order the best damn plate resistor I can find! Or maybe I'll check out constant current sources...

I liked the sound I had before, but with the diode biasing and the optimized voltage, it has improved beyond my expectations. The crystal clear floating highs I had before are still there, but the midrange has blossomed and the bass is to die for. Well worth the time and effort.

Baranyi, I bought it from Mick - came with remote, balanced output and far too many inputs for my liking.

Chelvam,
Did you buy NOS or is Mick manufacturing again?

Thats corect

chelvam:

if i'm not mistaken, when looking at the back of the chardonnay, the two sets of rca jacks to the right are preout 1 & 2. then the sets starting from the left are inputs 1, 2, 3, 4. there may be a tape loop in there somewhere between input 4 and preout 1.

look at this picture for reference:

http://www.6moons.com/audioreviews/supratek/3.jpg

Hi,

Just received my Chardonnay. Good packing. The only problem is, Mick forgot to include the manual. Anyone can help me out here? Thanks

Kg, if you observe the main photo in http://www.mentalpixel.com/supratek/history.html with the words "need a group photo here" and from there you can guess why it was horrible made. I agree the website is not helping Supratek's image. Maybe, I will email Mick about it.

I was about to get a used Nagra PL-L then I read somewhere Chandonney sounded better then Nagra and I hope so. I don't chase equipments. I got a very good room built for stereo playback and happy to just upgrade when I positively identify an improvement. I even discarded a high End speaker cables for a 6N OFHC China cable and no difference I can tell.

chelvam:

i was wondering what was up with that site as it was horribly made. i hope mick didn't pay much for that. good luck with you chardonnay. i owned one, but sold it and moved up to a dual cabernet. now that i'm getting into vinyl, i sometimes think i should've gone with a cortese instead. c'est la vie.

Yes, I have seen. Metalpixel is just an advertisement company. Go to the original website of supratek.

Arkio, my Chandonney is being couriered today. For almost 10 years I did not change my Classe Amp or Preamp but discovered the missing element (which I always knew missing but can't quite put my finger on it) when I tried a blue circle preamp except the bass was not right. Please don't ask me to define "right". If you been to live music (not the loud or open air type) or orchestras often you can tell the diff. So keeping my fingers crossed Supratek will finally give me the sound I want.

has anybody seen this site:

http://www.mentalpixel.com/supratek/index.html

it's copyrighted 2007. the front page looks decent, but the rest of the site looks like somebody had no idea what they were doing.

anywho, does anybody know who manufacturers the supratek remotes? i'm trying to get the hex codes for it so i can program my squeezebox remote to control the volume of my dual cabernet.

Chevlam,

How did you get in touch with Mick? I tried the phone numbers on the website and one is disconnected, the other goes to a builder.

Simon

Mick uses an expensive variety of Sika-Flex, a long lasting temperature resistant polyurethane cement/sealant. Like the Selleys gutter sealants its designed to last 25yrs+. He once told me besides the convenience of it, it also has good damping properties and stops the caps rattling and vibrating against the metal chassis.

Regards,

Steve M.

Jtgofish, so, has adhesive technology come a long way since the 90s as well?

I can't see any broblems with glue-as long as it is the appropriate glue for the job.Adhesive technology has come a long way since the 50s-when,no doubt, it was unsafe to glue in components.
I use new technology adhesives in eveything I make and these have rendered obsolete older technoloqies involving fasteners.

Hey Chelvam,
Congrats, you will love the Chardonnay. I recall Mick saying he would build some units here and there after he said his shop was closing up. I actually got a refund some time ago from him for a Sauv I had on order for over a year. He just could not oblige building it, so I got my deposit back. No worries. Sounds like he or his assistance(s) have some time now. I hope you don't end up waiting too long for your unit. I hope Mick opens up his shop again on a full time basis. I sure would like to get a Sauv or Cabernet for a second system I am putting together.

cheers and good luck.

I got a used Cortese in May. The original owner had excellent care to it - no scratch or dings. Yet on opening the package I sensed something came loose inside the power supply.
Removal of the bottom lid revealed one of the big capacitor did come loose, plus a slight free play on the toroidal transformer. There is a black foil on the bottom side of the top plate, and all the components rest on this foil. Part of the black foil holding this capacitor tore/peeled off. I figure that this must be the result of rough handling on shipment (from Southern California to Canada) and the black foil/glue holding the capacitor had become aged due to immense heat cycles on daily uses (Cortese users know the top plate of the power supply runs very hot).
With the guideline from Micy & Kevin (Thanks Micky & Kevin for your advice), the transformer was tightened back in place, and GE Sealant was applied to put the cap back in position. Kevin also warned me not to remove the phono tubes (as this time I don't have a T/T) as this will affect the bias.
I did not open the pre-amp unit as there is nothing came loose. This makes sense as it runs much cooler than the power supply.

It always amazes me, when somebody like Ralph (Atmasphere), who makes amplifiers for a living, makes a statement regard. proper building technics, in this particular case about why one should NOT use glue to secure parts to the chassis, there always be the other guy, with no professional experience of building anything, who would argue the opposite point, and will support his argument with a ridiculous and irrelevant statement, like " I do it all the time (use glue), and haven't had problems yet".
Puts other opinions of that same guy into a certain perspective, doesn't it?

It sounds like the original glue used is pretty strong. The concern I would have as a manufacturer would be what happens a few years down the road? The glue is aging, and also subjected to heating cycles. You know that it will degrade in due time. It is guaranteed that no matter how good the preamp sounds, if it is found responsible for a heart attack due to shock or burning someone's house down, the brand loyalty will mean nothing during the lawsuit.

One of my Syrah's phono battery holders was glued, and had come loose. Thankfully it was just the battery case and not a power supply cap...

I too used Goop to secure my Solen PP filter caps when I replaced the electrolytics in my Chenin, but I also made a steel bracket that I screwed into the wooden side of the unit just in case. Do I think the Goop will come loose? No, but a little extra safety doesn't hurt.

I am not aware of any of the parts coming loose from any inmates that own Supratek. Opened mine up to upgrade some caps and all was intact. The caps I replaced should not have come loose in shipping unless the unit was really banged around meaning probably damaged. It took some effort to remove the glued caps. I don't see them coming loose. If you were to buy one used as it looks like not to many are being made now, it wouldn't be a bad idea to open up the bottom and make sure everything is tight. I used "goop" to glue in the new caps. They are not going to move with this stuff! It appears that Supratek is still up and running on a smaller scale. Good to know. Love my preamp.

Chelvam, I've seen photos of the insides of 2 Suprateks (one photo is in a 6moons review). In both, the filter caps in the power supply were not secured by any hardware, instead were simply glued to the inside of the unit. This is a Bad Idea even if you are doing a DIY project. One drop in shipment (or otherwise) and you have a shock and fire hazard situation.

Mabil555, I just read all your earlier posts and found the answer to my question.

Atmasphere, his website did not state he is closing shop. Perhaps, he wanted to quit but didn't do it or just doing it on small scale. BTW, which parts were glued together? The Chrome plat? That's normal and sometimes it is also possible for the customs to rip off to check them and glued them back. I once received Koala bears from Australia all ripped apart by customs for inspection.

Maril555, I am sorry to hear your unfortunate situation. Are you still having the Amp?

It's interesting to hear Supratek is taking orders.
Maybe there is a hope, Mick will pay me back from the proceedings.
I have to admit- my hopes have faded quite a bit.

I was under the impression that Supratek had folded some while back- maybe a year ago or more. If they are back, I certainly hope that the new product does not have the same construction technique of using glue to hold components in place (as this represents a significant fire hazard).

Kevin Covi is a name I have seen before though- I am sure he knows better than that.

Hi guys, I just ordered my Chardonnay on June 5th. I think Supratek is still in business. My friend(who got the experience in repairing countless high end equipments, including one ongaku) is familiar with his previous venture - Micrex and he recommended me to go for it even though no one in my country seems to own one.

So, I guess this thread is going to go on for along time to come.

Thanks for the info Ait. I'll see can I get my hands on the GZ33. Just to mention, I was using the GZ37 on the Syrah for about 6 years, so it had a good innings. It really was so beautiful compared to the Bendix I'm using now which seems a bit hard/etched - it's subtle, but I hear it. Anyways, happy listening.