Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tdvt on March 08, 2024, 07:49:53 am
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At a band practice the other night, I decided to test-drive a Bassman combo project that I had just built a cabinet for, no electronic work. I only moved from it's original head cab to the new 12" combo.
Plugged into channel 2, it sounded good, until it would intermittently crackle & go half-volume for a split second, akin a bad instrument cable, but the cable was good. Power tubes were not flashing, wiggling the pre-amp tubes didn't help.
I pulled the chassis back out, cleaned tube sockets, etc. & eventually found a broken solder joint where the V1 cathode grounds to the brass plate. It looked to me like an original puddle of solder, so maybe the failure was 58 years in the making...
I am posting as I was using the vibrato channel only & I am wondering if that V1 issue could/would have caused problems downstream & account for what I was hearing?
On the bench, the amp seems OK, but I have not yet had the opportunity (volume-wise) to really test it out. So the question is sort of more hypothetical than not.
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Hypothetically speaking, that broken ground on V1 cathode is not responsible for the momentary volume drop on Channel 2.
More interesting, where did you find a bassman with a vibrato channel? :icon_biggrin:
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More interesting, where did you find a bassman with a vibrato channel? :icon_biggrin:
That would be a trick, wouldn't it?
That NORMAL channel gets around...