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Ampeg V4-B Hum troubleshooting tips request

Discussion in 'Amps and Cabs [BG]' started by deiseldave2001, Feb 21, 2002.

  1. I bought a 1970's V4-B a while back, and can't get rid of the 60 cycle hum. New tubes, new caps, cleaned pot's and tube sockets. Still humming! Any tips?
  2. if it's like the one I owned, does it have a 3-prong grounded plug? Mine didn't.

    I guess this is too easy, but what about the Hum Balance control on the back? I never had a problem with hum, even without the grounded plug.
  3. Thanks everyone, In response to: Does it hum without an input plugged up?
    I will check the caps you suggested. Thanks.
    I have adjusted the hum control, and it has not cured the problem.
    It sounds like 60 cycle to me, maybe a bad diode or 2?
  4. gmann


    Mar 1, 2001
    Contact Dennis at Central Jersey Repair in Edison, N.J. He worked at Ampeg in the early 70's. If he can't help you no one can.
  5. Psycho, the hum control helped. But not the solution. As far as your other concerns, I am an electronics tech in the telephony industry, and am aware of the dangers of 500+ volts. I also have been a working musician for 20 years. I just feel like this problem is something simple like the caps you mentioned. I'll try that, and let you know.
  6. Psycho, definately no negativity drawn here from your safety concerns. I have similar mantra's that I deliver on subjects that I am more at home with (like "whoa! never say that to your pregnant wife").
    It sounds like you have more tube experience than I do, and I appreciate you taking the time to offer suggestions. I will definately check the caps in question. So let it be written...

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