Tubes for my CJ PV-12

Discussion in 'Tube Audio' started by samwise801, May 17, 2018.

  1. samwise801

    samwise801 AK Subscriber Subscriber

    Messages:
    262
    Location:
    Salt Lake City, UT
    Greetings! I'm bidding on an AK auction, and suppose I should ask before I *acutally* win...does anyone know / care to opine on how well some RCA 5963s would work in my Conrad Johnson PV-12? I'm totally new to tube-audio, so I have no idea what I'm doing...

    I presume if the slot calls for a 12AU7 tube, I can put any 12AU7 tube in there and it will work, albeit with differences based on the particulars of the tube in question. Is that correct? And I have no idea what my PV-12 uses its AU7s for, whether it's for a phase splitter function or not.

    I guess what I'm really asking is, would this be a dumb auction for me to win if I'm planning to use these only in a PV-12?
     

     

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  2. maxhifi

    maxhifi AK Subscriber Subscriber

    Messages:
    2,340
    Location:
    Edmonton Alberta Canada
    I would say buy European ECC82 tubes. There's only two, and 12AU7s aren't that expensive I'd just throw in a pair of Mullard/Philips/Amperex/Valvo/Telefunken etc, bolt the cover back in place, then sit back and relax, knowing it's about as good as it's gonna get.
     
  3. samwise801

    samwise801 AK Subscriber Subscriber

    Messages:
    262
    Location:
    Salt Lake City, UT
    Fair enough, thank you!

    My PV-12 does have a phono stage, so there are four add'l tubes to account for over there -- another 12AU7, two 12AX7s, and one 5751. Currently everything in it is stock, and while it seems to be functioning okay it (and it's tube compliment) is 20ish years old...
     
  4. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,467
    Location:
    Glen Burnie Md.
    Only 20???? I've got tubes in gear that's close to 67 years old and they are still kickin ass, and taking names. Most of the tubes I run in my consoles are originals or close to it in age. And they are ALL over 53 years old (Youngest console is a 1965 FISHER.) Tubes will last a long time as long as you Don't abuse them. In other words listen at reasonable levels, keep them fairly cool, and NEVER SHORT CYCLE the POWER Switch. And find a schematic for the C-J. and figure out exactly where each tube is in the circuit or what circuit.
     
  5. billyz

    billyz Active Member

    Messages:
    235
    Location:
    Spokane
    The 12au7’s are the line stage amplifier and includes a cathode follower.
    The cathode follower is a bit hard on the 12au7 in the pv12.
    Many 12au7’s developed noise after a short time in this circuit.
    One of the most reliable is the RCA cleartop. I had several bad experiences with the very expensive Mullard box plate tube. There are many good choices though. I am currently using a set of 6189 tubes and they sound very well rounded. The pv12 is quite rewarding with tube rolling, you will hear what the tube sounds like and the best quality vintage tubes are well worth the effort.
     
  6. billyz

    billyz Active Member

    Messages:
    235
    Location:
    Spokane
    The 5963 tube could work as a sub for the 12au7 . You will have to try them and see though. They were a computer tube and not specifically designed for audio.
     

     

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  7. Palustris

    Palustris Well-Known Member

    Messages:
    725
    I have re-tubed my cj PV-4 twice; both times with a full set of tubes from conrad-johnson. After the first 20 years, I sent my PV-4 back to c-j for a full checkout and refurb. I would suggest that would be my first step if I bought a 20 year old PV-12.
     
  8. samwise801

    samwise801 AK Subscriber Subscriber

    Messages:
    262
    Location:
    Salt Lake City, UT
    Ya, I’ve thought about doing that, esp since the original owner thought he heard the left channel going out a little bit.

    Mind if I ask what CJ charged you for the re-furb?
     
  9. Palustris

    Palustris Well-Known Member

    Messages:
    725
    It was 15 year ago! I can't remember. I also sent my PV5 back for a refurbishment but can't remember what that cost either.
     

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