Marshall JMP Master Volume 20W Build

Marshall Amp Discussion

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Littlewyan
Posts: 1911
Joined: Thu Sep 12, 2013 6:50 pm
Location: UK

Re: Marshall JMP Master Volume 20W Build

Post by Littlewyan »

Sounds good to me. I'm tempted to add a few mods like that but have held off for now.

Yeah I had to use a non-CT PT which add some complications. Not the end of the world though.

I actually thought this amp sounded quite harsh with the master volume low until I changed out V2 in it. It was a JJ ECC803S and I replaced it with a JJ ECC83 MG. Much better!


One day gldtp99 I will build a monster amp like that! Until then Ill stick with my 20W and 50W amps :P. Try and find a 4x15 Cab for that Superlead and move into Lemmy territory!
gldtp99
Posts: 226
Joined: Wed Jan 03, 2007 9:21 am
Location: N. Texas

Re: Marshall JMP Master Volume 20W Build

Post by gldtp99 »

The guy that bought my 6V6 x 2, 2204 type head brought his band over to try out amps---- they played a Motorhead song while they were there----- the bass player was going through my Metro 100 watt MV head (KT88 x 4) when it was still in mostly stock 2203 configuration.

One way to go about building a bigger amp is to pick up an old Sound City 120--- gut the orig circuit and use the big orig iron and EL34 x 6 with the preamp of your choice---- you get a very solid steel chassis with plenty of pre-punched holes for the preamp tubes so you can configure almost any preamp you can come up with.
The output section on those amps is powerful and great sounding---- I think the 120 watt rating is very conservative with these monsters.
More power than most people would ever really need----- this is the output of one of the Hiwatt preamp SC 120 conversions I did early on:

Image

Sometimes these old amps can be picked up cheaply.................. gldtp99

PS: The owner of the SC 120/War Elephant (high gain single channel) amp I did says it "Comes Through" in live rehearsal/gigs better than other big high gain amps he has----- "Power" has a way of penetrating, and can be heard/felt, without being blastingly loud in some situations------ but Power also penetrates through walls, ceilings, floors, etc and can get the police called on you sometimes.
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Littlewyan
Posts: 1911
Joined: Thu Sep 12, 2013 6:50 pm
Location: UK

Re: Marshall JMP Master Volume 20W Build

Post by Littlewyan »

Ah yeah they come up on Ebay every now and then.

Power definitely gets through the walls in my house! I can't even play a 1W amp in this house without everyone hearing it!
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