Vibrolux Reverb Filter Caps

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Guitar Dave T, Jun 15, 2006.


  1. Guitar Dave T

    Guitar Dave T Member

    Messages:
    9,026
    Joined:
    May 15, 2006
    Location:
    Somewhere near White Rock Lake, N. Texas
    Looking through my books, I cannot find a schematic or layout for my amp, a 1967 Vibrolux Reverb AA864.

    Can someone please tell me what filter capacitors are SUPPOSED to go in this amp?

    Next question, was the amp originally designed for 110 VAC or 120?

    Finally, If the amp was in fact designed for 110, what would be the correct filter cap values for today's 120 Volt power?

    Background: There are 12 year old IC caps in there right now. They are reaching the age that I can justify replacing them with some Sprague Atoms.

    Thanks,
     
  2. Dave C

    Dave C Gold Supporting Member

    Messages:
    1,359
    Joined:
    Jun 10, 2005
    Location:
    Waterford Ct
    Sorry , I couldn't find an AA864 either, but a AA964 shows 5 -16mf/450v caps and 117v mains. I wouldn't worry about the ac mains difference in this case. The caps would be the same anyway. I'd use Sprague 16 or 20mf(leaning to 20's)...also used IC 22mf/500v with good results in a pinch.
    12 yrs is probably the expected lifetime for caps , but I've seen plenty still running with 40+yrs on 'em. I think at that age.....it's just a matter of when they're going to fail though and new ones will usually sound way better anyhow.
    Dave C
     
  3. Blue Strat

    Blue Strat Member

    Messages:
    29,990
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    From memory, they're 16ufs all the way across, just like a Deluxe Reverb.
     
  4. TheAmpNerd

    TheAmpNerd Member

    Messages:
    1,063
    Joined:
    Sep 23, 2004
    Location:
    Tejas
    They are 16uf across, with the mains wired in parallel (32uf).
    Same from AB763 - A1270.

    I'd dump the ICs in a heart beat.
    Spragues are okay, Nichicons better, Jensens better still.

    As long as you are in there, might as well replace the
    bypass caps too. Start everything fresh and you'll be
    a happy camper for years.

    Enjoy.
     
  5. Blue Strat

    Blue Strat Member

    Messages:
    29,990
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    At a bare minimum, replace the bias supply cap inside the chassis. This single $1 part can take out your power tubes and/or OT when it becomes electrically leaky (usually with no visible indications).
     
  6. AL30

    AL30 Member

    Messages:
    2,971
    Joined:
    Jul 20, 2005


    Not trying to derail this thread but I'm curious. AmpNerd you are the first person I have heard recommend certain caps over Spragues. Could you please elaborate on this? I'm not arguing I'm just interested in your opinion/experiences on this. Thanks

    AL
     
  7. TheAmpNerd

    TheAmpNerd Member

    Messages:
    1,063
    Joined:
    Sep 23, 2004
    Location:
    Tejas

    I understand.

    Those are my opinions/experiences based on what I've used,
    what I listened to, etc; along with some of what we used
    at Bell Labs/Lucent Tech. : )

     
  8. Guitar Dave T

    Guitar Dave T Member

    Messages:
    9,026
    Joined:
    May 15, 2006
    Location:
    Somewhere near White Rock Lake, N. Texas
    Interesting. How would you describe the difference between the Jensens and Spragues? What is the final impact/result of using the Jensens?
     
  9. TheAmpNerd

    TheAmpNerd Member

    Messages:
    1,063
    Joined:
    Sep 23, 2004
    Location:
    Tejas
    Both Nichicon and Jensens sound and feel better than Spragues.
    Clark uses these in his amps for a reason as do others.
    Also check out the following link:

    http://www.jensencapacitors.com/audio/white-papers/default.asp

    Try it, you'll like it.
     
  10. slider313

    slider313 Silver Supporting Member

    Messages:
    7,284
    Joined:
    Jul 28, 2005
    Location:
    NC
    I use two 20uf@500v for the mains and 3 16uf@475. This brings the total to 40uf on the main power supply filters instead of 32uf. Not a big difference but a little tighter and won't put a strain on your rectifier tube.
     

Share This Page