Calling All Marshall Experts

glpg80

glpg80

Well-known member
I need help for a dilemma.

I’m not a Marshall expert and never have claimed to be one. I recently invested into a Fawn 1979 Marshall JMP 2203 50W in mint condition. I've always wanted an early 81 JCM800, but recently learned about JMP's being the predecessors to JCM800's.

I scored the amp in mint condition. But here's the thing, it's in too mint of a condition. I'm scared to gig the thing or to really use it or even mod it to put a metro loop in and a resonance knob in one of the speaker jacks. I've secretly always wanted a 100W since they have a stronger bass response and sound larger, but I've been told that 50W marshalls are more desirable for lead tones and "give up the goods" better.

I've spent maybe 20 minutes playing it and it does have the JCM800 grind, but I don't really know what to do. I've considered trading someone who has a regular headshell JMP ~1974-1978 100W, but at the same time I know just how rare these Fawn models are.

What should I do?

Thanks RT!
 
As long a you bought it right you might be able to flip it for some gain. Unless it is a 68 plexi or a 69-70 superlead I don't think the market is all that hot collectorwise from what I have seen lately. Play it some more and see if grows on you. FWIW my 1979 2203 100 watter, with a TS808, SD-1 or MXR Dist+ was the most aggressive and best sounding Marshall I ever heard until the PT crapped out in the 90's, it ate JCM800's for breakfast when side by side. My old guitar player still talks about that amp to this day, he bought an 83 JCM800 50 watter and it was a dog. I think the early JMP's 2204 and 2203 were better sounding for some magic reason, probably components and alot still had Mustards in them instead of the lego caps.

If the amp has a documented provenance you can prove it could have more collector value.
 
It has original 6550's in it and not EL34s. It sounded alright but could use a re-tube in the pre-amp IMHO. It is definitely aggressive but the second you go for a solo it's all clean notes. It's not the most gained out 2203 I've played, but again I believe it's due for some new glass and needs a boost.

I could probably break even on trade. I know I'll need an attenuator and a boost to really get the most out of it. Would it be worth scoring a 100W over my current 50W?
 
glpg80":3uowfv84 said:
It has original 6550's in it and not EL34s. It sounded alright but could use a re-tube in the pre-amp IMHO. It is definitely aggressive but the second you go for a solo it's all clean notes. It's not the most gained out 2203 I've played, but again I believe it's due for some new glass and needs a boost.

I could probably break even on trade. I know I'll need an attenuator and a boost to really get the most out of it. Would it be worth scoring a 100W over my current 50W?
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6550's don't like a hot bias, bias them at 50-60% dissipation max. My 79 had about 460DCV on the plates. Run a EH12ax7 or Mullard Reissue, TungSol 12x7 in V1, V2 a Chinese or a JJ/NOS that will stand up to cathode follower voltage, V3 whatever you like best here, short or long plate modern or NOS. if it has the original GE6550 they can last for years just don't bias them hot, they lose their definition and tight low end with a hot bias ie. 70% and they can go into runaway bias at hotter bias as well, that's why Marshall used 150K grid leak resistors instead of 220K that the EL34's use. I truly believe the original transformers sound best in these JMP years over the JCM800 years. If you find you want the punch of a 100 watter I would only go after a 75-80 2203 and play it first if you can.

I have a 72 50 watter SL and it sounds great but it does not sound as big and have the low end punch my 100 watters do, the 100 watters just punch better IMO at any volume level. If you want the ultimate 80's 90's tone without modding run an SD-1, OD808 or OD of your choice into a Parametric EQ into the Marshall front end.

I agree with LPfreak,if you are not impressed with the amp tone after some tubes and a good tech check and bias then send it out the door Fawn cabinet or not. I've had amps that just were OK and they were not satisfying to play...period, down the road they go.
 
exo-metal":1os0lsh5 said:
paulyc":1os0lsh5 said:
Keep it and play it. Don’t worry about it.
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This...
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:rock:
What boost pedals do you have? IMO to get the goods out of any 2203/4 you gotta boost em. A little or a lot, they love a decent boost pedal. SD1, 808, Cusack, Timmy, and on and on....I go between an OD1X and a Maxon 808 in front of my 800 and they both do it differently...but sound killer. Hell you can use 2 boosts at once for metal mayhem.

My experience with 2203/4s are they are all good, some incredible. The 82s have been absolute steamrollers, something about that year and the power sections...devastating. Other years are hit or miss. I've never played a bad one though. 50s are a little sweeter sounding. But I usually go for the 100w for the bigger tone.
One thing I always do with any Marshall is max the presence, and start the treble off and dial it up slowly, that will give the amp bite. Kerrang. Whatever.
 
harddriver":27ax4vya said:
glpg80":27ax4vya said:
It has original 6550's in it and not EL34s. It sounded alright but could use a re-tube in the pre-amp IMHO. It is definitely aggressive but the second you go for a solo it's all clean notes. It's not the most gained out 2203 I've played, but again I believe it's due for some new glass and needs a boost.

I could probably break even on trade. I know I'll need an attenuator and a boost to really get the most out of it. Would it be worth scoring a 100W over my current 50W?
Click to expand...

6550's don't like a hot bias, bias them at 50-60% dissipation max. My 79 had about 460DCV on the plates. Run a EH12ax7 or Mullard Reissue, TungSol 12x7 in V1, V2 a Chinese or a JJ/NOS that will stand up to cathode follower voltage, V3 whatever you like best here, short or long plate modern or NOS. if it has the original GE6550 they can last for years just don't bias them hot, they lose their definition and tight low end with a hot bias ie. 70% and they can go into runaway bias at hotter bias as well, that's why Marshall used 150K grid leak resistors instead of 220K that the EL34's use. I truly believe the original transformers sound best in these JMP years over the JCM800 years. If you find you want the punch of a 100 watter I would only go after a 75-80 2203 and play it first if you can.

I have a 72 50 watter SL and it sounds great but it does not sound as big and have the low end punch my 100 watters do, the 100 watters just punch better IMO at any volume level. If you want the ultimate 80's 90's tone without modding run an SD-1, OD808 or OD of your choice into a Parametric EQ into the Marshall front end.

I agree with LPfreak,if you are not impressed with the amp tone after some tubes and a good tech check and bias then send it out the door Fawn cabinet or not. I've had amps that just were OK and they were not satisfying to play...period, down the road they go.
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This. Bias them about the same as El34's in a Marshall. Maybe a little bit hotter. The output transformer impedance is for EL34's, so a 6550 cannot run optimal with the Marshall transformer. You will never get 35 watts per tube in a Marshall circuit out of a 6550. It is not louder per se than a 34; just a different tone.
 
LP Freak":fzk4iwpz said:
If you have a doubt dump it. It’s obvious you’re not sold on it.
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Mainly because I’m new to getting the Marshall tone I’m after. I really want to chase the no more tears album tone which I know was a jcm800 combo with post processing effects. This is my very first Marshall I’ve ever owned and I’m not sure whether it’s a solid platform to start from? It’s more user error here.

Thanks for all of the replies dudes. Sounds like I need to check the bias of the GE6550s, put some new glass in the preamp, and run my para EQ into the front of it and see what happens. I do need a reactive load to run it into as well and have been needing one for a while.

I do enjoy the bigger tone of a 100W but don’t mind the soloing sweeter tone of a 50W. Marshall’s are loud bastards either way, just one has more punch in the gut than the other.

If it doesn’t sound good after all of this, I’ll send it off and play an earlier model JMP. I played this one before grabbing it and know it has potential.

Thanks for the reassuring comments. I’ll shut up and play it a while and see what happens from here ?
 
Sell this one and get a 100 watt amp. I prefer 100’s a lot more. Tons of balls.

Here is my 100% bone stock 1980 JMP 100 watt at slightly louder than TV volume with a Klon Clone out front. Amp is loaded with original GE 6550’s and Chinese C8 Preamp tubes.



https://youtu.be/e6Uj_DBTe58
 
Psychodave doesnt play fair. He can dial in badass tone and has chops. But he did give a great piece of advice.

I believe the preamp tubes he is referring to are the military ones that i get on this forum from snave. Those are the dogs balls in my opinion for gain. I suggest you score some for you amp.
 
rottingcorpse":2fhggw85 said:
Psychodave doesnt play fair. He can dial in badass tone and has chops. But he did give a great piece of advice.

I believe the preamp tubes he is referring to are the military ones that i get on this forum from snave. Those are the dogs balls in my opinion for gain. I suggest you score some for you amp.
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Haha. Thx.

I have 300+ of those C8’s. :LOL: :LOL:

Back to the original topic, I like the different head shell idea as well...but only if the amp is a killer sounding one.
 
psychodave":2mrmy5z3 said:
rottingcorpse":2mrmy5z3 said:
Psychodave doesnt play fair. He can dial in badass tone and has chops. But he did give a great piece of advice.

I believe the preamp tubes he is referring to are the military ones that i get on this forum from snave. Those are the dogs balls in my opinion for gain. I suggest you score some for you amp.
Click to expand...


Haha. Thx.

I have 300+ of those C8’s. :LOL: :LOL:

Back to the original topic, I like the different head shell idea as well...but only if the amp is a killer sounding one.
Click to expand...
:rock:
Marshalls are THE most sensitive amps to tube swaps of all the amps I've tried. Just a swap in V1 alone can make a huge difference, and vintage Marshalls LOVE vintage tubes, including the Chinese military 6N4s. It's amazing the difference in tone when I do some pre tube swaps. Mullard, Amperex, Ei, Tungsram, Telefunken, RCA, even GE NOS pre tubes all sound a bit different from one another, with the Chinese 6N4 being the most aggressive of them all.
 
glpg80":2m4o4ebu said:
Mainly because I’m new to getting the Marshall tone I’m after. I really want to chase the no more tears album tone which I know was a jcm800 combo with post processing effects. This is my very first Marshall I’ve ever owned and I’m not sure whether it’s a solid platform to start from? It’s more user error here.
?
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That amp should get No More Tears Zakk tone easily. I think Dave is running a Duncan Distortion pickup or an Aldrich in his 1980 2203 vid with the klon clone, his vid only reinforces my view that 78-80 2203 have some magic to them. The C8 or even C9 Chinese are pretty good preamps and can handle the V2 position in Marshall.

Recommendation for NMT tone. High output pickup of your choice> Chorus pedal of your choice>Boss SD-1>Parametric EQ to taste(not necessary but nice to have)>Marshall>Celestion 12-H30 or equivalent, EVM-12L if your want 100% accuracy even a Vintage 30 would work, I like the Mesa V30. If you don't get that tone then the amp is either broken or a dog. Since those years usually are not dogs then the former could apply. Let us know how the experiment goes.

If it gets the tone and feel you want keep it and either install the metro loop or use get a Fryetter Powerstation PS2 with the available loop and you get your attenuator as well.
 
psychodave":1mdastw3 said:
Sell this one and get a 100 watt amp. I prefer 100’s a lot more. Tons of balls.

Here is my 100% bone stock 1980 JMP 100 watt at slightly louder than TV volume with a Klon Clone out front. Amp is loaded with original GE 6550’s and Chinese C8 Preamp tubes.



https://youtu.be/e6Uj_DBTe58
Click to expand...


Out of curiosity which Klon clone is that?
 
harddriver":3dgi1xh8 said:
psychodave":3dgi1xh8 said:
Sell this one and get a 100 watt amp. I prefer 100’s a lot more. Tons of balls.

Here is my 100% bone stock 1980 JMP 100 watt at slightly louder than TV volume with a Klon Clone out front. Amp is loaded with original GE 6550’s and Chinese C8 Preamp tubes.



https://youtu.be/e6Uj_DBTe58
Click to expand...


Out of curiosity which Klon clone is that?
Click to expand...

Ceriatone. I built it myself.
 
Sounds like fun to me!! Damn, sure that's not a kemper or axe effects? :doh: Lmaool. I know that's not even funny to consider. That seriously is badass tone.
 
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