Help with an old ampeg v4b

Discussion in 'Amps and Cabs [BG]' started by cliff em all, Jun 10, 2020.

  1. cliff em all

    cliff em all

    Jul 6, 2012
    Hey guys! I recently got an ampeg v4b for a really low price. The first day of use it was sounding monstrous and everything was functioning. I was running it through a furman power conditioner and when I went to shut it down I switched it to standby, power off and then completely turned off the furman. This is my first experience with a tube head and did this all relatively quickly. By the time I turned off the furman head i heard a pop and got a small jolt from touching the metal. Since then the ampeg has been completely dead with no signs of life. I’ve never worked on electronics or much less an ancient tube head so I have no idea where to start looking. Anyone have an idea what this could be?
  2. Gibson Victory

    Gibson Victory Gold Supporting Member

    Dec 21, 2019
    A lot of these older Ampeg tube heads usually end up having a variety of issues, for various reasons. Bad tubes, dried out caps, and so forth. Maybe at some point someone has even attempted a mod or repair at some point. TB wise you might want to try an get in touch with Agedhorse for starters. Then branch out from there. Internet wise the Fliptops people sound like a place to start. Just a suggestion.
    matt11 likes this.
  3. matt11


    May 19, 2006
    That’s a bummer. I love my 74 v4b. Best to take yours to a good local Ampeg tech. Don’t try to fiddle around in there yourself, and at all costs avoid touching the transformer—they can hold a significant charge for a while.
    Gibson Victory likes this.
  4. Gibson Victory

    Gibson Victory Gold Supporting Member

    Dec 21, 2019
    Amen X 2 !
    matt11 likes this.
  5. xj98jeep


    Jan 3, 2016
    Small jolt from touching the metal sounds like a failed death cap which is a somewhat typical failure for the old V4Bs, and for sure needs to go to a qualified tech. Probably also a few other issues like others have said. Flyback diodes, fuses, random shorts, etc
    Gibson Victory and matt11 like this.
  6. BassmanPaul

    BassmanPaul Inactive

    This is a very good reason to leave the amp alone. There are lethal voltages present even with the amp unplugged. A tech is a wise investment and his/her price is much less that your life is worth.

    Oh and ditch the Furman!
    JimmyM and Gibson Victory like this.
  7. Gibson Victory

    Gibson Victory Gold Supporting Member

    Dec 21, 2019
    Amen X 2