Lets talk Marshall's JMP versus SLP ect

  • Thread starter Thread starter cragginshred
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LP Freak said:
Guys would laugh if you had a picture of that amp šŸ˜‚
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It was seriously one of the most impressive sounding high gain/modded Marshall type amps Iā€™ve played. No joking matter! I would take it all day over the Cameronā€™s. That guy needs to make more of them

Itā€™s cool when guys step out the box like that. Besides that being a stereo amp, some of my favorite vintage speakers were also made for that purpose and guitar guys donā€™t know about them
 
LP Freak said:
I wish someone wouldā€™ve gotten a picture of it so they knew what you were talking about
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Here it is below. They can laugh all they want, but it would put to shame the vast majority of other modded Marshall type amps. Asked many times if heā€™d sell it LOL
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Racerxrated said:
I agree with most but I feel my 72 punches harder, with equal clarity/definition than the 2010 MC100 I had, with the C transformers. And thatā€™s with a simple modern Distortion pedal in front. Maybe the ā€˜harder punchā€™ is a perception though since the Marshall has noticeably better mids than any Wizard, imo.
But this amp is also a good notch above that 69 Marshall I brought to the fest, which you heard and liked. The 72 is bigger, more 3D/Rich sounding even with a pedal, than that 69.
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I think your 72 is a unicorn because many 70ā€™s era Marshallā€™s sound like straight dog ass without a lot of help from going through them for drifted components, recap, bad switches, outboard pedals for boosts, etc. I seriously wonder if your 72 is even stock at all šŸ˜‚
 
glpg80 said:
I think your 72 is a unicorn because many 70ā€™s era Marshallā€™s sound like straight dog ass without a lot of help from going through them for drifted components, recap, bad switches, outboard pedals for boosts, etc. I seriously wonder if your 72 is even stock at all šŸ˜‚
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Well, I learned long ago to look to the Marshall forum for anything Marshall related. When it got here I took pics of the circuit, looked at the caps (previous owner said it had 2 pots replaced, a couple small caps) and fired it up. Sounded great. Posted the pics of the circuit to 2 guys on the Marshall forum(Tazin, and Neikeel) and they both chimed in with 2 pots changed, 2 small caps and the PT was a non original Dagnall. Those guys know their shit. Eventually I located a T3556 which is period correct, 1970-73 higher voltage PT and swapped it in. Sounded even better.
So, mine was gone through in England before I got it, which was confirmed by the 2 MF guys I mentioned, and needed nothing.
I think I remember one of your Marshalls, the filter caps blew up? Or it hadn't been run in years? For that type of amp, an 'attic' special I of course would have my local guy go through it. But, luckily for me all the vintage Marshalls I've owned (except 1 that had powder coming from the bottom of the caps) had all been gone through by a tech/checked over before I got them...they've all been killer.
Oh, and those two MF guys said my 72 is completely stock and original except for those parts I mentioned above.
 
glpg80 said:
I think your 72 is a unicorn because many 70ā€™s era Marshallā€™s sound like straight dog ass without a lot of help from going through them for drifted components, recap, bad switches, outboard pedals for boosts, etc. I seriously wonder if your 72 is even stock at all šŸ˜‚
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That would make my 72 another unicorn as well as the others I've played. My tech did go through mine any to make sure, but it didn't need anything according to him. Of course they don't have a lot gain without a boost or mod, but they're killer for what they are with very hard hitting brash upper mid punch and openness. It's not I think a sound everyone here would love, but imo killer for what it is
 
Racerxrated said:
Well, I learned long ago to look to the Marshall forum for anything Marshall related. When it got here I took pics of the circuit, looked at the caps (previous owner said it had 2 pots replaced, a couple small caps) and fired it up. Sounded great. Posted the pics of the circuit to 2 guys on the Marshall forum(Tazin, and Neikeel) and they both chimed in with 2 pots changed, 2 small caps and the PT was a non original Dagnall. Those guys know their shit. Eventually I located a T3556 which is period correct, 1970-73 higher voltage PT and swapped it in. Sounded even better.
So, mine was gone through in England before I got it, which was confirmed by the 2 MF guys I mentioned, and needed nothing.
I think I remember one of your Marshalls, the filter caps blew up? Or it hadn't been run in years? For that type of amp, an 'attic' special I of course would have my local guy go through it. But, luckily for me all the vintage Marshalls I've owned (except 1 that had powder coming from the bottom of the caps) had all been gone through by a tech/checked over before I got them...they've all been killer.
Oh, and those two MF guys said my 72 is completely stock and original except for those parts I mentioned above.
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Yeah no one will believe me, but I bought my 74 120W 6550 Marshall for $850 in unknown ā€œas isā€ condition before covid. Thereā€™s a thread in the tech forum showing the whole gut and rewire/rebuild. Blown caps, corroded switches, bad wiring, it was a mess. It evolved into the enmity mod.

Whatā€™s youā€™re new plate voltage loaded? Did your tech say?
 
glpg80 said:
Yeah no one will believe me, but I bought my 74 120W 6550 Marshall for $850 in unknown ā€œas isā€ condition before covid. Thereā€™s a thread in the tech forum showing the whole gut and rewire/rebuild. Blown caps, corroded switches, bad wiring, it was a mess. It evolved into the enmity mod.

Whatā€™s youā€™re new plate voltage loaded? Did your tech say?
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Right around 490v, 500 somewhere in that range. The later 70s T4145 that was in it, the PV was 440. I do run it around 105v with a variac though; since these vintage PTs were designed for 110, not 120 which is why in my estimation a lot of these vintage Marshalls have replacement PTs.
 
This thread has exploded! As Marshall threads often do... listen, go with a JMP or just a 2204 800 circuit and do these two things to get closer to a Plexi on 10' for less dough. I always recommend this but once you hear it, you will realize you have seen the light.

1. Change the Negative feedback resistor from 100k to 47k (8 Ohm tap). Takes some of the teeth away but allows more bloom/roundness to the tone.

2. Get the MV UP and the preamp DOWN. If not, it is mush city. I like MV on 7 or 8 and the preamp down between 4 and 6.

That's it.. enjoy.

3. Extra credit: V2a "Cathode bypass Switch" mod. Just wire in 330pf and 68K ( tight tight tight) on a switch so you have options and diff feel. for the love of god do NOT clip your bright cap.

That's it. This recipe cooks and it's all I have found I need. Not quite as tasty as a Superlead balls out but not all the SPL have the gain you want. Most 2204/800 can get closer to that gain and they will be tighter. This versatile circuit with a few tweaks is all those tones from early Def Lep to mattias Jabs, to even AC DC. ( Angus has essentially turned his Plexi's into 800's so he can control MV)
 
I'll throw another curve in the thread lol.
79 jmp 2203,6550s,clean ch,fx loop installed by " Erickson Audio" WA.
I bought this locally.Previous owner doesn't know much about it.It sounds pretty good,transparent loop and a bit more than stock gain on tap.
Anyone heard of this guy from Washington state and his mods?
20240118_215901.jpg
 
SpiderWars said:
Something happened here; either you or Dave got it reversed.

It is the 50w models that had the low voltages; as low as 390v. I have one. I have also had 2203s and they all had ā€˜normalā€™ voltages (say around 450v) or higher.

Also, the 50w non-MV models of the 70s were low voltage (had those also) and they just kept using the same transformers when they started making the 50w MV models.
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Yes I re read my post and re read his e mail several times to be sure -YES 50 2204 can be 'squishy' with lower plate voltages. He also said
he could mod it back up
 
I have a confession Rigtalkā€¦. I have never played a plexi, superlead, superbass, supertremā€¦jtm 45 or anything. Just an 800, 900, dsl, tsl and a jvm. And other than the jvm and 800, the others were just tinkering around with for five or ten minutes.
 
JackBootedThug said:
I have a confession Rigtalkā€¦. I have never played a plexi, superlead, superbass, supertremā€¦jtm 45 or anything. Just an 800, 900, dsl, tsl and a jvm. And other than the jvm and 800, the others were just tinkering around with for five or ten minutes.
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The amps youve played above can get any of the other amps sounds no problem.
I will say old Marshall prices are insane and just keep going up like taxes & inflation.
 
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