Conrad Johnson PV-10A mod experiences?

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.

since last post I have actually made 3 changes. (1) in general I prefer to stay within manufacturer specs and I was curious about the Obbligatos so I've swapped in a 0.15uf Obbligatto to replace the Rel RT 0.1uf. So far its nice, sweet sounding, no negative consequences. More to come after I get some burn in time on it. (2) replaced the slow GI 854 8818 diodes (ttr =200) with Hexfred TXYS 15A 1200V soft recovery diodes (ttr=40). A very pleasant change eliminating what before I thought was "digital hardness" in recordings. However all is not completely well in Mudville as the hard percussive sounds (block bell) have lost some authority and I'm suspicous that other transient areas are damped. So will be swapping these out for "BY228TR, Vishay 3.0A 1500V" sinter glass diodes next when they arrive... these have an even lower Time To Recover (ttr)than the other 2 and no soft recovery characteristics. Mean time I can enjoy listening at an extreme end of tube sweetness.

Now for change 3 which was an unexpected positive surprise. After much fussing with various 12ax7's and replacing the bare wire board jumpers I was still no farther ahead with eliminating the phono section rushing noise that occured at about an 11 oclock position (my normal playing level). I decided to swap in 12AU7 instead. Big smile on my face as I turn the volume knob all the way up and not a rushing sound to be heard. Granted, my normal playing position has now changed to 1 oclock but sound is gloriously quiet, musical and all 12AU7's tried are quiet.

So more to post later once the new diodes arrive.

sorry, busy with other things. So since last time
1) in the phono bypass caps the 0.15uf obbligatos were nice, open sounding... however the cap casing is a hum magnet and microphonic. So yanked them out and threw in some Mundorf Supremes temporarily
2) the Vishay sinter glass diodes are great, fast. Believe I'm there for power supply clean up
3) seems the rushing noise finally cleared up completely in the phono section after I rechecked lead proximity and cleaned up solder joints.

I plan 1 last step, to add VCap teflons as the phono bypass caps at end of month. These do take about 60-90 to break in which would be about May to report back.