Ampeg PF-50T Making Clicking/Switching Noises

Discussion in 'Amps and Cabs [BG]' started by BM Wilde, Dec 7, 2018.

  1. BM Wilde

    BM Wilde

    Dec 7, 2018
    Hey All,
    I've had this amp for about a year or less. No problems until last week when it started humming (low hum) and it sounds like its... switching? I've replaced the preamp tubes but I'm waiting for the new 6L6s to show up. So far that hasn't helped (I know, why would it?). Could it be power tubes? The amp still plays, it has power... I'm stumped.
  2. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    To rule a few things out - you don’t have a cell phone or wifi router nearby when this happens do you?
  3. BM Wilde

    BM Wilde

    Dec 7, 2018
    @coreyfyfe , nah, but good thinking! I should try another outlet just to rule it out. It's weird because it's never moved from that spot.
  4. BassmanPaul

    BassmanPaul Inactive

    Maybe it’s looking for a change of location. They get bored just sitting in one spot! :D
    lowendrv and ahc like this.
  5. BM Wilde

    BM Wilde

    Dec 7, 2018
    Oh Paul... hahahahaha!
    BassmanPaul likes this.
  6. warranty?
  7. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Fortunately, tubes for it aren't too darn expensive, but while it could be the power tubes, it may not be, too, and no reason to replace tubes that aren't bad. Have you tried lightly tapping the power tubes while it's on to see if one of them could be bad? A lot of times, bad tubes can be detected this way. Not always, but usually.
  8. BM Wilde

    BM Wilde

    Dec 7, 2018
    @JimmyM I found a couple of brand new JJ 6L6s and they may have helped with the clicking/switching sound. There still a really low hum that isn't affected by volume, input or anything like that so maybe it's the transformer? Luckily it's still under warranty!

    Thanks for the reply! :)
    JimmyM likes this.
  9. rickdog

    rickdog Gold Supporting Member

    Mar 27, 2010
    Were the new 6L6s a matched pair? A push-pull output stage depends on good balance to cancel hum, so poorly matched tubes can result in some hum.

    Does the PF-50T have a control to adjust the balance? I haven't seen a schematic for it, does anyone have one?

    Since the amp doesn't have any problems other than the hum, the problem is really unlikely to be the transformer, so rest easy.