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Half-burned amp while testing a circuit?

Posted: 18 Jul 2011, 04:21
by moveoverover
Hello everyone.

I never posted here, but i plan to start doing it from now on.
I was testing some bias of a 2N3904 BJT, in a breadboard, and the output was connected to a 60watt valvestate amp (solid state combo). When I reached a bias that had some high gain, and after a few seconds of (gently) playing with my guitar, I noticed from the smell that something was burned in the amp (and it was a bit noisy too). I had the amp with the volume knob almost on the minimum, cause I was at home. The strange thing is that the amp still works but it's a bit noisier (I hear some cracks and pops). What could be the problem and what could have caused it?
I didn't know that I could wreck an amp with this. Maybe the speakers, but not the amp itself. I want to try the circuit in my Fender Deluxe but now i'm worried that I might burn it too (lol).
If any one could help i would be grateful.

Thanks,

João from Portugal.

Re: Half-burned amp while testing a circuit?

Posted: 18 Jul 2011, 05:03
by DrNomis
moveoverover wrote:Hello everyone.

I never posted here, but i plan to start doing it from now on.
I was testing some bias of a 2N3904 BJT, in a breadboard, and the output was connected to a 60watt valvestate amp (solid state combo). When I reached a bias that had some high gain, and after a few seconds of (gently) playing with my guitar, I noticed from the smell that something was burned in the amp (and it was a bit noisy too). I had the amp with the volume knob almost on the minimum, cause I was at home. The strange thing is that the amp still works but it's a bit noisier (I hear some cracks and pops). What could be the problem and what could have caused it?
I didn't know that I could wreck an amp with this. Maybe the speakers, but not the amp itself. I want to try the circuit in my Fender Deluxe but now i'm worried that I might burn it too (lol).
If any one could help i would be grateful.

Thanks,

João from Portugal.

It could be that a resistor might have gotten a bit hot in your Valvestate Amp... :hmmm:


Do you have a coupling capacitor on the output of the circuit you were testing?, if not, that might have fed DC into your amp's input and caused something to overheat through conducting too much current.... :hmmm:

Re: Half-burned amp while testing a circuit?

Posted: 18 Jul 2011, 05:52
by moveoverover
DrNomis wrote:

It could be that a resistor might have gotten a bit hot in your Valvestate Amp... :hmmm:


Do you have a coupling capacitor on the output of the circuit you were testing?, if not, that might have fed DC into your amp's input and caused something to overheat through conducting too much current.... :hmmm:
Yeah, I had. But now i'm not sure if i took it for a while because of some noise i was having that was due to the multimeter.. It could have been that.
I guess it's better to open the amp to find out what is burned after all.
Thanks