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Marshall Amp upgrade questions.
Old 21st November 2002
  #1
Gear Head
 
🎧 15 years
Marshall Amp upgrade questions.

I have a 1976 Marshall JMP 2x12 50 watt Combo. It is a 4 input version, not a master volume. I am going to take it in to the shop for a tune up and upgrade. I have 2 questions.
1) Does Marshall still make replacement filter caps for these amps? If so, are they the best thing to put in, or can you put in something better?
2) It currently has 2 rola celestion speakers, one of which is torn. What is a good speaker to match with this amp. I am looking for smoother sounding breakup, preferably at somewhat lower volume settings. I'm not sure speakers have much to do with this, but if anybody has any preferences, please let me know why.
Thanks!!!
MG
Old 21st November 2002
  #2
One with big hooves
 
Jay Kahrs's Avatar
 
🎧 15 years
#1. I have no idea.
#2. Look into either a Celestion Greenback or a Vintage 30. The Greenback will break up faster then the 30, but the 30 has more low end and is a bit clearer.
Old 21st November 2002
  #3
Gear Head
 
🎧 15 years
Manny, I recommend checking out the Plexi Palace and Weber VST websites for upgrade info on tube guitar amps. Both sites have forums with more information on Marshall-Vox-Fender care and feeding than was previously known to man. Good luck.
Old 22nd November 2002
  #4
Lives for gear
 
groundcontrol's Avatar
 
🎧 15 years
I find the Greenbacks can sound harsh in an open back cab and this particular model of Marshall already have a tendency to get a bit strident, so I would suggest checking the vintage 30's. On the other end, I sometimes like having two different speakers on a combo amp for studio work, this way you double your tonal options and the resulting sound of the amp can be a little more 3 dimensional. Just some ideas...

Good luck!
Old 24th November 2002
  #5
Gear Head
 
Lars FM's Avatar
 
🎧 15 years
Agree on the greenbacks being to harsh. My suggestion would be to check out the G12H30, the V30 is good but a little boxy/midrangey sounding IMO, depends on the sounds wanted though. All i can say is that the G12H30 is probably THE 70's rock speaker FWIW.

Lars
Old 24th November 2002
  #6
Gear Head
 
Lars FM's Avatar
 
🎧 15 years
regarding changing filter caps, i wouldn't go for "Marshall" caps as they put whatever is cheap but working inside their amps. Ask an experienced tech about what to do, but be aware that your amp will probably get louder and cleaner from a change of filter caps, but most likely less noisy as well.

Lars
Old 24th November 2002
  #7
Lives for gear
 
groundcontrol's Avatar
 
🎧 15 years
Quote:
Originally posted by Lars FM
All i can say is that the G12H30 is probably THE 70's rock speaker
Lars, how about 25 watts Alnico black dots? heh These grggt ROCK grggt in old style 4x12 stacks.
Old 25th November 2002
  #8
Gear Maniac
 
Mats Olsson's Avatar
 
🎧 15 years
Just a thought: anybody fitted a 412 cab with 4 different speakers?

I have found Marshall cabs to sound much better with improved bracing, better internal cables and some acoustic wool + sealing with silicone.

/Mats
Old 25th November 2002
  #9
One with big hooves
 
Jay Kahrs's Avatar
 
🎧 15 years
I've never done four different speakers in a cab but I've run into two different kinds a few times. The most common seems to be a pair of Greenbacks and a pair of Vintage 30's. After Lars comments I think I want to check out the G12H30's. My guess is that they're probably cheaper then the Green's or V30's which is always a plus. Personally I'm not a huge fan of the 75 watt Celestions that come in the new non-reisse Marshall 4x12's. I haven't bothered to change mine yet. It's pretty low on the list of things to do but I'd like to get around to it one of these days.
Old 25th November 2002
  #10
Lives for gear
 
groundcontrol's Avatar
 
🎧 15 years
Quote:
Originally posted by Jay Kahrs
Personally I'm not a huge fan of the 75 watt Celestions that come in the new non-reisse Marshall 4x12's.
Me neither!
Old 25th November 2002
  #11
Gear Head
 
Lars FM's Avatar
 
🎧 15 years
Quote:
My guess is that they're probably cheaper then the Green's or V30's which is always a plus
In Europe they are about the same as the other two

Quote:
Lars, how about 25 watts Alnico black dots? These ROCK in old style 4x12 stacks.
Haven't tried those unfortunately, but i know the 15w alnico, and thats a kick ass speaker in combo's as well as 4x12's. A totally different flavour though and i wouldn't trust them to cope with a 100w or even a 50w Marshall in the long run. Worth a try though (if money is no subject)

Mats, the multi model speakers into a single is an interesting idea, would give plenty of choices for multi miking, haven't tried it though, but i might be able to give it a try in a not too distant future.
Could you describe the mods to the cabs that you mentioned?

I forgot one thing, the V30 DOES record rather well as far as i remember, haven't A/B'ed anything so no real comparison to the others mentioned.

Lars
Old 26th November 2002
  #12
Lives for gear
 
groundcontrol's Avatar
 
🎧 15 years
Quote:
Originally posted by Lars FM
I forgot one thing, the V30 DOES record rather well as far as i remember, haven't A/B'ed anything so no real comparison to the others mentioned.
You're right, that's where all those mids get useful!
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