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AD30HTC -- No Sound -- Help Appreciated

Posted: Sat Jul 27, 2019 1:03 pm
by DrGnosis
Hello there,

So I was starting into the first song of our set with my amp going into the 16-ohm input of a backline (and beat up) Marshall 1960A cab, everything was fine for a few seconds, then the volume starts dropping, and a strange smell started coming from the amp (not necessarily a burning smell). I immediately turned everything off and ended up borrowing another amp (combo; not through the cab).

I took it home, hooked it up to my 16-ohm cab, and I didn't get any sound on either channel -- not even a hint of noise. I changed every tube 1-by-1 (both preamp channels; power EL84s; and rectifier tube) to no avail. I changed the HT fuse -- no help there. I took out the chassis to take a look under the hood, and there were no visibly evident abberances.

Here's the kicker -- the tubes still light up. I ended up dropping it off with my amp tech, but I was just wondering if anyone had any ideas as to what the problem might be.


Re: AD30HTC -- No Sound -- Help Appreciated

Posted: Sat Jul 27, 2019 2:00 pm
by Jondog
You took care of the basics providing those components were good, so tough to say. Definitely right idea taking it to the tech. I’ve had solder joints go, traces burn off, components like resistors fail, loose wires etc... Hopefully its something simple like that. Getting power is a good sign.

Re: AD30HTC -- No Sound -- Help Appreciated

Posted: Mon Jul 29, 2019 7:15 pm
by Les Paul Lover
If the valves light up, it means that valve heater power supply is still going - since that come from the main power transformer, it seems to indicate that it's still good, though the other windings in it could still be affected, they usually fail altogether.

Could be the a variety of things really. Hopefully you'll get it back soon enough in perfect working order!!!!