'65 Bassman snap/crackle for fist 10mins

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Timinator, Feb 11, 2008.

  1. Timinator

    Timinator Supporting Member

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    Is it time to send this in for a facelift? The "cracks" are pretty loud, like a wire short. In fact, I think it even sends this crack signal to the cab while it's in standby. Once it warms up all noice goes away and it's heaven. Thanks, Tim
     
  2. wgs1230

    wgs1230 Fully Intonatable Silver Supporting Member

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    Short answer: yes. If you're hearing noise through the speakers with the amp on standby, there's a decent chance your output transformer is in trouble (though it could be a bad connection on either end of the speaker line and the OT will be fine once it's corrected). Don't wait for a catastrophe, take it to a competent tech.
     
  3. Timinator

    Timinator Supporting Member

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    Yep, they are all original. Any competent techs out there somewhere closer to Ohio than further? The one person out here just passed away and there appears to be no respectable people to take his place. Tim
     
  4. Nolatone Ampworks

    Nolatone Ampworks Silver Supporting Member

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    Tim said the cracking sound hit the speakers even it standby.

    Could the filter caps downstream of the choke cause that? The initial filter caps certainly wouldn't in standby.
     
  5. MisterAgreeable

    MisterAgreeable Member

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    Those first two filter caps are isolated from the OT by the standby switch. I can't see how they could make noise in standby.

    The only things energized while in standby are the bias circuit and those filter caps, none of which should make sound come from the speaker. If you're sure it makes sound while in standby I would guess an intermittent short in your standby switch, which seems remote.

    Could the noise be coming from inside the amp, not from the speaker? Do you think it would make noise if in standby with no speaker attached? (If so I would stop using the amplifier until you've identified the problem.)
     
  6. Timinator

    Timinator Supporting Member

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    OK, forget the standby switch, I messed up. I forgot I was A/B'd to two amps. It does it with no input signal, not on standby. The sound is a loud click followed by big background buzz and hum for a couple of seconds then loud click an it's off for a few seconds. Then it does it again. Sometimes longer sometimes shorter. Tim
     
  7. Nolatone Ampworks

    Nolatone Ampworks Silver Supporting Member

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    Then the filter caps seem a likely culprit especially since they are original.

    Maybe you can sell em on Ebay as "vintage Fender Caps" :)
     

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