Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ElPedro on February 09, 2016, 08:02:35 pm
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So a guy brought me his peavey artist 240 to fix. Said he's not getting any sound out of it.
This amp is a discreet preamp with 6l6 power section.
I have replaced all of the big power filter caps and other larger electrolytics. Voltages look good at the tubes, running around 460 or so.
Here's what's happening- when I take the amp off standby I can get max volume for a couple of seconds. Then volume goes very faint, but steady. When I take the amp off standby, I get a discharge of volume from nearly full volume down to zero.
Any thoughts?
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Maybe a test to isolate the problem?
If you could disconnect the preamp section, input say a test tone into your power amp, and see if you get the same symptom.
If the power amp keeps outputting a good test tone, for a reasonably long test period.
Then you could be pretty sure you have an issue in the preamp circuit.
Only other idea I had was that the PT is weak and going bad.
If you can isolate this to the preamp, that would be a good thing. :icon_biggrin: