Need help with an Ampeg SVT-3 Pro "popping"

Discussion in 'Amps and Cabs [BG]' started by billdeg, Mar 12, 2006.

  1. billdeg


    Mar 12, 2006
    Hi - I have a relatively new SVT-3 pro, but I assume it's no longer under warrantee.

    Here the question:
    Sometimes with no bass plugged into the amp, but with the amp plugged into speakers, the speakers make a popping sound every few seconds. You can see the speakers themselves flex or pop out, but the actual pop sound itself is not too loud.

    I have experienced this phenomenon with multiple cabinets. It does not matter which speaker outputs I use, and I have tried swapping out speaker cables - no effect. It's almost certainly the amp. The problem has occurred in four different locations so I don't think it's a particular building's electrical system.

    I can usually get it to stop popping by pulling in or out the ground lift knob on the back of the amp. It's totally unpredictable. One day it will work fine, and then the next with the same gear it will not, and then the next it will work fine again. Sometimes it will be fine for a couple of weeks and then it will start again. Sometimes I can't make it stop by changing the ground lift.

    What is wrong with my amp? I don't want to use it for shows until I get this resolved. Is it just the tubes or is there some kind of grounding/electric issue?
  2. Fuzzbass

    Fuzzbass P5 with overdrive Supporting Member

    The 3Pro I used to own also had noise problems: it was occasional snap-crackle-hiss-pop rather than just pop. The noise was fairly loud, but only audible between songs, and it would stop within a half-hour after the amp was turned on. I always suspected it was the tubes, but never bothered to swap them so I don't know for sure. I wound up building a second rack rig using an Ampeg SVP-Pro preamp so I sold my SVT3Pro. I didn't sell it because of the noise, btw... only because I didn't need it any more.