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Peavey microbass guitar amp

Hello i have just got a peavey microbass and when i switch it on it hums very loud, iv taken it apart and one of the chips is dammaged it is slap bang in the middle of the board with 5 terminals going into it, and is screwed to what seems to be aluminium block, can i get a replacement chip??
please email me on

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Re: peavey microbass guitar amp

The hum is usually electrical mains hum at 50hz, i wouldn't recommend messing about with the insides of amps!

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Guitar amp continuous humming from speaker

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Hum or buzz is often caused by the mains filter capacitor letting the 50hz mains hum into the system. Regardless of voltages you just need to try new capacitors. If that doesn't cure it, the problem is elsewhere. If it's a stereo amp and the buzz is on both channels then it's something common to both channels.

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It could be the diodes, but whatever is the cause it's before the pre-amp section. Generally a loud hum such as that with no effect by volume control, is mostly caused by the filter capacitor in the power supply. And that hum is the 50HZ mains hum getting into your system!

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I have a Peavey Valve King 112. When I plug in my guitar I get nothing.The power light is on and the preamp is on as well.There is just silince.No humming or crackling.

This could be anything. You could try swapping the preamp tubes. If it were a power amp tube problem, it is likely the mains fuse would have blown, Since the pilot lamp is still on, we will assume that the problem is at the preamp level. This absence of signal can be caused by a dead tube, or more complexly, by a faulty resistor or capacitor in the signal path. If you can't resolve the problem by swapping preamp tubes with a known good one, you should take the amp to a tech experienced in servicing tube guitar amps. Any good tech should be able to sort this out within an hour of labor time. I doubt it will require any expensive parts. It may even be as simple as a loose/bad connection, either from manufacturing, or from normal use. Pro tube amps are subjected to levels of heat, vibration and electrical stresses that consumer electronic gear never sees.

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I have a Peavey Microbass 20 watts and I need the schematics in order to repair it myself. I'd apreciate any advice to find this papers.

These are available from Peavey, but not for free. Expect a cost in the $20 range. Contact Peavey directly and ask for either service or parts.


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Hi, Peavey Classic Guitar amp , Has NO SOUND

Hi Mike,

If you switch on the amplifier, do you hear nothing at all?
Or do you hear low level noise or hum out of the speaker?
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A peavey special 130 guitar amp with excessive hum

I used to have one of these years ago!

What do you mean when you say 'switch to the off position'? Do you mean it hums when switched off?

Because the sound does not fully follow volume, it is likely a bad connection or power filter capacitor is not working.

Either way, it means a trip to a repair shop. There is nothing in there you can fix unless you are a repairman. Your local music shop should be able to coordinate a repair.

If this amplifier is like the 1983 version I had, its built like a tank and the fix should be easy.

Hope this helps!

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