Blown Amp

[ABG123]

Hi. Just joined the forum. I have a 50-watt Marshall Valvestate amp that I blew out. I was jamming with a drummer, had the volume up pretty loud and was using a Fulltone Fatboost, which I usually don't do. After about ten minutes the amp went silent. There was a funny smell and now if I play through it the signal comes through, but is extremely low and muddled. I opened up the amp and the speaker looks fine. Anyone know what might have happened?

I'd like to repair it if possible. It's a great little combo for me.

Thanks.

[52 Bill]

I opened up the amp and the speaker looks fine. Anyone know what might have happened?

Welcome to the place. Looks can be deceiving, test the speaker to eliminate it as a problem.

If you have another speaker cab around try plugging it into the amp and see what happens. If you have another amp around try plugging the speaker from the Marshall into it and see what happens.

Does the amp light up and channel switch and everything else as normal?

[Enzo]

Obviously I don't have your amp in front of me, but my sense tells me if it makes sound at all, the amp is probably not blown so much as just has a problem. Might be a power supply failure inside, but could be a bunch of things. We'd have to go inside with a voltmeter and start looking.

[ABG123]

Thanks for the suggestions, guys (and thanks for the welcome, Bill 52).

I have a Marshall 4x12 I could plug the AVT's speaker into and see what happens. With an amp that's mostly solid state, if it's not a speaker problem would it even be worth it to have someone at knowledgeable music store try to trouble-shoot/repair it? Just wondering how much it would cost, if they're willing to do it.

[52 Bill]

What you want to find out is whether the problem is in the amp part or the speaker. If you plug the amp into another cabinet and it makes full sound, then the problem is in the speaker. If the amps still plays dead through the other cabinet then there is a problem with the amp part.

A fast test would be to unplug the speaker from the amp. Now take a 9 volt battery and touch the battery terminals to the speaker terminals or the plug. If the speaker is working you will hear a loud pop from the speaker. If the speaker does make a loud sound, then I would guess that there is a problem with the amp circuit. If it doesn't make a loud sound, then try the amp through another cab test.

[ABG123]

Wow, I'm going to try that 9-volt battery trick first. Very cool.

Thanks!