Conrad Johnson PV-10A mod experiences?

also replaced the stock electrolytics on power supply section with Nichicon fine gold caps but that didn't seem to cause a noticeable change

ok so the upgrade bug is hard to stop. I've now upgraded in the pre mains section the 13.5 uf solens to 2x 6.8 uf Mundor Supremes and replaced the 10uf Solens with same in Mundorf Supreme. A wonderful improvement, gobs of tone color detail, accompanying players get the same clarity as the lead line. At first listen I was worried I'd just put in a high pass filter... no cymbal sheen. Now after 25 hours of play, all has evened out and Mundorf Supreme has my utmost respect for musicality at an affordable price.

When my PV-10 (that I had for 17 years)needed repair (a tube arced and blew it out), I sent it to Bill Thalmann at Music Technology. IN addition to the repairs, I had him do his mod package (which included replacing the original caps with "auricaps", among other changes). The pre did sound more accurate and "faster," but it may have lost some of the ambience and warmness that it had originally. Unfortunately, I don't know if it would have improved over time, because after a few months, the same thing happened again (probably my fault, I put in a tube I shouldn't have). Unfortunately, Bill never responded to my E-mails after that. I couldn't afford to have it fixed again, so I sold it as is, and went back to solid state (Emotiva, with a Yaqin CD-1 tube buffer). Personally, I was never happier with my CJ than when I had a Bugle Boy and an RCA triple mica black plate 5751 in the line, and Telefunkens in the phono. The mods made a difference, but I was always happy with the original sound of the PV-10. (great midrange and phono stage). I've always had a SS amp (Adcom, then Classe).

Just wanted to add that you would get Auricaps in your power supply with the Backert mod that I mentioned above.

Deleting the crappy electrolytics is one reason that it makes a preamp sound so incredible.

It's a bit over $700 for a CJ. The price varies with other kinds of preamps. Instead of the Auricaps, you can ask him to use V-Caps, and it's still only $900. But the Auricaps are already a HUGE upgrade compared to the stock electrolytics.

To my knowledge, there is no other power supply on earth that gives you teflon caps, like V-Caps. It just doesn't exist. I think this is why he is getting it patented.

Cheers,
Hukk

Have continued to work on this as the board layout is easy to work with. Since last post I have taken out the 2uf Solens SE capacitors in the phono and pre sections because of "edginess" and replaced them with REL Theta's. In the phono section I have substituted Rel RT 0.1uf values (the original 0.15's have few quality manufacturer options). In the pre section I have swappped out a 13.5 Solens to 2x6.8uf Mundorf supremes, a 4.0uf Solens for a 3.9uf Mundorf Supreme, the power supply pair 20uf Solens for 20 uf Clarity TC series and replaced a 4700uf Electolytic
with a Mundorf MLGO.

Overall very pleased, none of the CJ character has been lost, just rejuvenated with greater transparency and extension in the highs. I plan over the next 90 days to take two additional steps before calling this done (1) the power supply diodes are original (slow), will replace with HiperFRED's (2) the phono section was remarked as not the quietest in the original product review, age hasn't changed this. There are a number of bare wire runs in the phono section and I'm suspicious of how close some of the cap terminal wires are to the tube socket contacts, will report if I find any steps that reduce the phono section noise.