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Help!!! Humming Vintage SVT!!!

Discussion in 'Amps and Cabs [BG]' started by XPshychoticXPyr, Apr 19, 2006.

  1. Hey guys so i just purchased a 1976-1979 ampeg SVT and the only issues with it is there is a noticable hum when it is hooked to a cab and not being played. Is this normal and if not does anyone know what may fix it?

  2. popinfresh


    Dec 23, 2004
    Melbourne, Aus
    My V8's started doing this.. I'm thinking bias or something..
  3. If you ever buy an amp second hand, especially an older one, i would always take it to a tech, when i got my SVT-II everything was fine until i suddenly got some really funky sounds, found out if i had been running the amp more i could have really screwed it up as one of the power tubes was completelly burned out and the rest had grounding issues!
  4. When I have bought my vintange Fender Bassman 100 alltube head, it had a strong hum when the master volume on maximum. I took it to a tube amp speciallist, let him changed all conds and tubes (plus tube pads).After that repairs the hum almost dissapeared. I am using it 3 years for all my gigs and rehearsals (jazz,big bands) - no problem.
  5. John P. Jones

    John P. Jones

    Jul 28, 2005

    I also own a Ampeg SVT '76-'79 and there's a knob, switch behind the frontpanel (at the right side) for adjusting the hum,...
    I've never tried it, but I know it's there,...
  6. metron

    metron Supporting Member

    Sep 12, 2003
    With old tube amps that hum I would guess (in my mostly uneducated opinion) that some caps need to be replaced.
  7. jz0h4d


    Apr 26, 2005
    Caps or bad tubes.
  8. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Hum balance control wrongly adjusted

    bad tube

    Capacitors etc

    Try in that order. Also in order of increasing expense....

    You'll want to run through those possibilities fairly fast, as hum, particularly if loudish, is not a good sign, and may signal a problem that can cause more damage.

    If the hum IS loud, probably isn't the balance control........

    New tubes OFTEN have heater-cathode leakage. Seems to be a standard feature, and it causes hum, or worse. Old tubes had that pretty well fixed.
  9. Turock

    Turock Supporting Member

    Apr 30, 2000
    Think of another tune.
  10. sedan_dad

    sedan_dad Supporting Member

    Feb 5, 2006
    It doesn't know the words!

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