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Late 70's Marshall JMP Master Model 50w Mk2. Lead


The high input has a cascaded gain stage. The low input is like a normal 1959 (Super Lead).


It's fairly easy to mod a super lead with a cascaded gain stage and master volume. I did this to my '68 SB and the sound is awesome through a '68 4X12 with 55hz green backs. One of those full stacks in my avatar is mine. Purchased back in '71 from that short haired skinny guitar player from Houston. No beard yet when picture taken. It's actually a super bass. He used two and they were too loud, so he sold one.
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Power User
I've asked this before and would love to see the late 70's 100W JMP model in the Axe FX. I'm always up for tweaking amps, but without the physical amp I feel it's impossible to tweak the existing models to make them sound like the JMP. That's simply because I have no idea how the JMP should sound like.
This may seem like a stupid question but, if you have no idea what the jmp should sound like, why would you love to have one in the axe?


Power User
There's a really nice 1981 one for sale on Reverb but it's in Canada. Debating whether I should buy it.
I dare you...

But seriously, I know it's a no-go but I think there's a lot of support in the Fractal community for a crowd-funding for amps to go into the Axe... A reserve of untapped capital. Just a hint. ;)


Power User
I already got my hands full with a 4-year old who's way too smart for his age.

I act like a 4 year old



Fractal Fanatic
I love my AxefxII. It' stuff like this that basically means I'll be upgrading even though I don't need to. It's too much fun to be a part of. The more FAS products we buy the more amps and stuff Cliff can buy and we get a stream of continuous return on investment. How is this not the best gear investment ever?


I may have the schematics somewhere, I can look for them tomorrow. I have a buddy who passed in 2009 who specialized in guitar tube amp repairs and I Inherited some books and technical documents. Fingers crossed.


There were 2 varieties of those amps. The first 50 watt master volumes had parallel inputs:

The later ones had the cascaded input like the JCM800:

If yours has the cascaded or series inputs, then I think you would be better off using the JCM800 amp.
If you have the earliest, series input model, then what Cliff said.

I believe these late 70's amps came with 6550's...everyone I knew wanted there amps changed back to el34's but back in those days, some el34's would simply melt down. Another tube, and it has been alleged that VH used this tube, was the 6ca7. These amps varied from 350vdc to over 450vdc and also varied greatly in the way they sounded from amp to amp.
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