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Conrad Johnson PV-10A Upgrade

Mojofilter17

Mojofilter17

Member
All - don't know if this is the right place but I'm looking for help/advice on upgrading a Conrad Johnson PV-10A tube preamp. This one has the phono section. The lot-date code on some of the big caps is mid 1991.
I am replacing all of the polypropylene caps. I heard some where to leave the polystyrene caps alone. Replacing all five tube socjets with gold plated ceramic ones. Of course, new tubes.
What else should I consider replacing while I'm in here?
Thanks in advance.

- Tim
 
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Don’t be fooled by gold plated anything. Don’t put in ceramic sockets. A possible upgrade might be Belton sockets because these sockets grip the pins extremely well.

The stock CJ caps were pretty good. Whether or not new caps will be an upgrade depends on the caps you’re thinking of using.

Right I would leave the polystyrene caps alone.
 
Thanks kward, I ordered the Belton sockets. - out of curiosity, why not ceramic sockets? The PV-10 is reputed to run on the hot side so I thought ceramic might stand up better.
Strangely, the top cover for this preamp has no vent holes, sides or top. There is a row of slots along the top of the back panel.
Jantzen Supreme Z caps were highly recommended on several forums. Can't afford the Teflon caps.
 
I'm with kward on the sockets; all of the gold plated ceramic types presently available are absolute garbage. In addition, the plating is so thin that after only a couple of insertions, you are right through the gold and into whatever scrap metal they used for the contact body. I use Belton exclusively, and in my own CJ PV5.

The original polypropylene caps are made by SCR in Chateauroux, France. They also manufacture the Solen brand. They also made many of the custom CJ-labelled capacitors. Good luck finding anything demonstrably better, as opposed to being "marketing wank" better.

Replace the three electrolytics, they're probably due by now.
 
I agree with others about not changing the caps. There are dozens of boutique caps out there, and you can spend a fortune trying them all, only to find that your CJ doesn't have the old "magic" it used to.

I recently decided to try changing the original Audio 1 oil caps in my Cary SLP98. What a rabbit hole! The whole character of the preamp changed, and not for the better. I finally did find one that worked--Fostex. It preserved the hearty tone of the originals with just tad more speed and transparency, and I do like it. But there are only four caps in the Cary so it wasn't a huge investment. All the same, I'm not sure it was worth all the fuss.

Also, the Cary is hard wired, so I could yank things around without doing much harm. You've got a PCB there and the chances of damaging the traces are very good. Then you've really got a mess on your hands. For the same reason, I wouldn't mess with the sockets unless something is broken.
 
Probably the only signal cap upgrade I would consider for the CJ gear is Teflon. I was going to do that for my PV12 but then went a different direction and sold the unit.
 
I have some Mundorf electrolytics showing up. There's only three of them so not too much trouble/$$. I am a retired EE and former owner of an audio repair shop so PCBs don't worry me.
The tube sockets have some pretty loose contacts so I've pulled them already. Don't want to try and tighten them. And I can imagine there are some crap ceramic sockets out there, so I'll go with the Belton.

I will leave the signal path caps alone for now, unless/until I run into an issue. They are ~30 years old by now so we shall see...

I do need some new RCA jacks however. The plastic or phenolic 'board' that all the I/O is on is cracked in several places, so I'm looking for some bulkhead/panel mount jacks that preferably include isolation washers. I want as good a quality here as I can afford - I don't mind paying a little more but I need some help here from experienced people out there. As mentioned above, there's a lot of crap out there.
Thanks!
 
The electrolytic in the mute timer became problematic in my PV5, and I put off changing it for as long as I could endure the ever-lengthening warm-up mute. Mine is not really a very service-friendly unit, so I ended up clipping out the old one and tacking in a quick replacement on the component side. When I finally did the electros and the sockets, it was not a lot of fun extracting/flipping the board.

CJ really did cheap out on the I/O parts. I like the REAN NYS267-x series. Really well made, not oversized, and not overpriced. Same manufacturer as Neutrik.

https://www.mouser.ca/ProductDetail/REAN/NYS367-0?qs=R5cXQUTKuHU8XkQYanQZXg==
 
Mojofilter17 said:
I have some Mundorf electrolytics showing up. There's only three of them so not too much trouble/$$. I am a retired EE and former owner of an audio repair shop so PCBs don't worry me.
The tube sockets have some pretty loose contacts so I've pulled them already. Don't want to try and tighten them. And I can imagine there are some crap ceramic sockets out there, so I'll go with the Belton.

I will leave the signal path caps alone for now, unless/until I run into an issue. They are ~30 years old by now so we shall see...

I do need some new RCA jacks however. The plastic or phenolic 'board' that all the I/O is on is cracked in several places, so I'm looking for some bulkhead/panel mount jacks that preferably include isolation washers. I want as good a quality here as I can afford - I don't mind paying a little more but I need some help here from experienced people out there. As mentioned above, there's a lot of crap out there.
Thanks!
Click to expand...

Ah, okay then. ;-) The Mundorfs are nice.
 
Mojofilter17 said:
Thanks kward, I ordered the Belton sockets. - out of curiosity, why not ceramic sockets? The PV-10 is reputed to run on the hot side so I thought ceramic might stand up better.
Strangely, the top cover for this preamp has no vent holes, sides or top. There is a row of slots along the top of the back panel.
Jantzen Supreme Z caps were highly recommended on several forums. Can't afford the Teflon caps.
Click to expand...

It's not as big of an issue with the octal output tubes- but ceramic sockets can be murder on miniature tubes, such as the input and phase inverter tubes. They're too rigid, and can produce stress on the tube pins. This can crack the glass on a miniature tube base, making the tube junk (air gets inside).

Also, the ceramic sockets have no damping. They can transmit vibration, and make microphonics worse.

Regards,
Gordon.
 
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