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I have a Peavey TNT 130. When it gets warm and I've been playing for a while it does this thing where if I play quietly (passive bass, high gain input) or I stop playing it seems to act like a noise gate is activated. It gets kind of fuzzy and buzzy and the volume drops to near nothing. If I thump it again it comes back to life. Seems to work fine as long as I don't play with any dynamics and it takes a while after turning on for this behavior to start. Any thoughts on what this could be? I'm leaning towards something to do with the pre-amp or the DDT compression circuit.
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Welcome to the forum.
My first thought is dirty switching contacts in the FX loop. Patch the preamp out to the power amp in socket and see if the problem disappears. If it does, the contacts need cleaning.
If no improvement,to establish where the fault lies (preamp or power amp) when it starts to act up plug your bass into the power amp in socket. This bypasses the preamp and if the fault disappears the problem lies in the preamp section. -
Thanks! And thanks for the tips. I don't actually use the effects loop, I just run straight in no pedals or anything. But ya, those are some good troubleshooting tips. I still suspect it may be something in the DDT circuit, any thoughts on how to test that?Comment
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The reason the FX loop fails is because it isn't used. The switching contacts don't get exercised and subsequently oxidise, causing all kinds of problems with signal loss, distortion and intermittent problems. That's the first thing to eliminate as the problem is really common.
The reason for plugging the bass into the power amp in socket is to 'divide and conquer'. There's no point in spending time troubleshooting the preamp if the fault is in the power amp. The return of the FX loop is a really convenient way to do this as it establishes which section is faulty.Comment
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Nice. Thanks again! Have a rehearsal today hopefully it'll act up again and I can check some of these things. Appreciate the input.Originally posted by Mick Bailey View PostComment
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Of course it went the entire rehearsal without a hiccup last night. I love intermittent problems!Comment
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Because it will respond to a thump, it is likely a bad solder connection, or dirty/oxidized pot or jack. A faulty DDT component would not respond to a thump, unless it was a bad solder connection somewhere within that circuitry.
Like Mick stated, the FX loop jacks are the most common cause of these kinds of symptoms. Dirty pots are also a common cause.Originally posted by Enzo
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