Marshal AVT20 Service

Nice clean ampNice clean ampSimple controlsSimple controlsChassis outChassis outReverb tankReverb tankSimple neat transistor circuit mini heat sinkSimple neat transistor circuit mini heat sinkSinle valve on it's own in the preamp section... All pots and sockets cleaned and then back togetherSinle valve on it’s own in the preamp section… All pots and sockets cleaned and then back togetherTested good but a little low gain, I put a higher gain one in thereTested good but a little low gain, I put a higher gain one in thereClosed back cabClosed back cab10" celecstion10″ celecstion Ideally I do not work on solid state amps but here is one I serviced for a friend

Not much to say here it came in not sounding quite right. Cleaned up the pots and sockets and put a higher gain tube in, sounding sweet now! (well for a tranny amp with one tube 😉 )

5 thoughts on “Marshal AVT20 Service

  1. Is it possible to modify this amp so that when an external speaker cabinet is plugged in such as a 1×12 vintage 30 the internal speaker doesn’t cut out to make it have a little bit larger spread of sound?

    • Potentially it depends on whether the combined impedance of the internal and external speaker together is below the minimum impedance of the amplifier in question.

      I would need to see the speakers you are thinking of using but should be able to work something out.

      Stewart

  2. Yes thank you, very helpful I’ve done a little reading on what you have said, I was planning on using the stock speaker that is 8ohms and a vintage 30 is 16ohms, so i think i’d need to replace the original with a 16ohm speaker re wire it so it is wired from the external speaker jack so when plugging in an extra one it would stay about the 8ohms……. I think this would be correct, but thank you for pointing me in the right direction.

    johny

  3. Yes thank you, very helpful I’ve done a little reading on what you have said, I was planning on using the stock speaker that is 8ohms and a vintage 30 is 16ohms, so i think i’d need to replace the original with a 16ohm speaker re wire it so it is wired from the external speaker jack so when plugging in an extra one it would stay above the 8ohms……. I think this would be correct, but thank you for pointing me in the right direction.

    johny

    • Great you have worked it out yourself. And changing the way the jack socket works is quite easy just link across the two connections on the bottom of the extension speaker socket.

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