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jmp 50watt lead mk2 1976 ?


rdpar

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I have this Marshall jmp 50w master lead head made in 1976. It is so bright that I have to turn the treble all the way off to get a good sound and it is still pretty bright. Any ideas on how to tame the beast. using kt88 tubes jj tubes

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yeah it sure is a bright amp. I'm using a jcm900 lead-1960 cab. so what ever came stock in that is what I got. Probably 70watt celestions. thought I would buy an mxr 10 band eq pedal and try that. I tried an alesis meq-230 and it worked fine to roll off more highs. so hopefully the eq pedal will work. thanks

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hey homewrecker. where do I find out how to do that.

 

 

I had a tech do it to mine when I had him go through and replace the caps, if you're not familiar with amps I'd highly recommend taking it a tech for a once over, something that old might need the caps replaced. But if you trust yourself I'm sure there's a bunch of DIY sites that can show you how to do it.

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yup just found a good forum. vintage amps bulletin board. thanks. will do it tomorrow.no problem.

 

 

Good deal man, I've also heard that when the pre is maxed it takes the bright cap out of the circuit, but I'm not certain of that. If that's still not helping I'd go with a tube swap, personally I'm not a fan of JJs but just but 5 or 6 pre amp tubes and swap them in and out of V1 until you find one that does what you want.

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Clipping the bright cap is FAR from ruining a vintage amp, you literally just snip one wire.

If it's stock & in good shape it's one of the finest amps made.

 

He sounds young, it starts with a nip & tuck, then it's extra gain stages>>> pretty soon it's not a JMP anymore.

 

Hate to see that happen to a classic, but i can't save amps cept my own...my.02

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so charveldan what would you reccomend I do to tame the treble excess. Oh and for the record if you are older than me God help you:) I'm just after the tone that is in my head and this amp is just too trebley.I am taking all suggestions. I sure don't want to butcher the thing

 

 

marshalljmp003.jpg

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  • 4 weeks later...
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I have the same amp, and mine is uncomfortably bright with all of my guitars.

LPs, JP Juniors, teles, etc.

 

Thing is, it didn't used to be this bright.. I swear it wasn't AS bright. Always somewhat bright when the master or pre is turned down

 

It sounds great when pre-amp and master are cranked, but then it's also unsuable. High sensitivity input when near 10 just squeals with any guitar.

Massive hum + hiss.

 

I replaced the filter caps about a week ago, no change.

 

I tried snipping the bright cap, but then the amp lost all balls. brightness was gone, but it also didn't have the note articulation that it used to have.

 

 

I've brought it to two 'well known' tech guys here, and one told me "it's just a noisy amp", and the other said to change the pre-amp tubes, which I did and it did nothing.

 

 

:( What am I missing *sigh* - if you have great results let me know.

 

maybe I just need a smaller value bright cap

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Is it a 2203 or a Non Master Volume model? Either way they are great amps , but they are painfully bright. Clipping the bright cap definitely isnt butchering the amp. Its very simple to remove and replace if you decide to. I do it on ALL of my old Marshalls.

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just trade it for a peavey xxx its the tone in your head!
:thu:

 

dude.. gross.

 

 

I have a 2204. it's painfully bright when turned down. Turned up it's bright, but there's so much else going on you don't notice it. Crushing tone, but so much noise it's anything but useful (a seperate problem entirely)

 

a friend of mine has a traynor yba-1 that I installed a PPI-MV into, and it works flawlessly. I might do the same to mine, and have a PRE-PI as well as PPI-MV.

Most of the

 

Here's video of me playing it, where I could crank it, . You can still hear the highs really coming through over everything,

 

gets lost in the mix after the start (ignore talking haha ... )

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cant you change the bright cap to a lower value one ??

 

 

That's what I plan on doing, prrrrobably tonight.

 

Come to think of it - I think it's got a 47pf cap on it right now. Looking at the schematic that's not right at all!

 

However, clipping it made it way too dark.

I've got some work to do...

maybe a rotary switch with like 5 different cap values!

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Head over to http://forum.metroamp.com Post that photo of your amp's circuit and I you'll get plenty of info on how to mod your amp to sound to your liking. You can even take a look at some of the amp-build instructions they have to get an idea what every part in the amp actually does.

 

You could convert your amp to partial bass/superbass spec to make it darker and tame some of that high-end. But, removing the bright cap is probably step one.

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