Preamp Deal of the Century

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.

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

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?

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.

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.