NAD (new to me): 1980 Marshall JMP 2104 50W (2204 combo)

After some asking around, emails & scouring the webz, I finally got a headshell for a head conversion.

Popped up in my Reverb feed last week - Made by Modulus amplification.

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The bottom mounting holes don't line up completely with the metal chassis but that should be an easy fix.

Now, need to find an aftermarket logo & replace the old Daly caps (which were tested by a tech & are good) with some F&Ts to really have that peace of mind.
 
Jack Luminous said:
If the caps are good, don't touch anything. Number one rule in all tech jobs : "Don't fix what's not broken".
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Fair enough but I don't like to risk it - if those crap out suddenly (they're 46 years old) & take out other stuff with them in the process. I'll take'em out and store them just in case I decide to sell this at some point in the very distant future.
 
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Already had this discussion on multiple boards. Gave my advice (good advice), based on personal experience, anecdotal evidence, multiple friends in electronic repair business for decades... Feel free to disagree.
 
I work in IT, the folks that say “don’t fix what isn’t broken” are usually the ones gripping onto legacy solutions and hurting their environment as a result.

It’s like “don’t change your spark plugs, they’re still working right?”
 
Components were never designed to last forever and the manufacturing of components in the 70’s wasn’t like stuff that is made now. Especially things that were shoved into Marshall amps.

Components age and deteriorate. There is a big difference between needlessly replacing parts that don’t need replacing, and carefully identifying places in the circuit that can be prone to failure. Filter caps, bias caps, grid stoppers etc are all worth doing if you want to protect the amp. As are things like changing death caps and making things safe to use.
 
MirrorProfiles said:
Components were never designed to last forever and the manufacturing of components in the 70’s wasn’t like stuff that is made now. Especially things that were shoved into Marshall amps.

Components age and deteriorate. There is a big difference between needlessly replacing parts that don’t need replacing, and carefully identifying places in the circuit that can be prone to failure. Filter caps, bias caps, grid stoppers etc are all worth doing if you want to protect the amp. As are things like changing death caps and making things safe to use.
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For sure. I mean this topic's pretty polarizing on most online forums.

I know Steve Fryette's in the "if they're good, don't change them" camp on recap-ing and it's fair enough - those Dalys in there give the amp a certain vintage / romantic vibe but I've weighed the pros / cons and decided to put in new ones for the extra safety (and hopefully gain a few more B+ volts as a byproduct).
 
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I cant imagine waiting for caps to fail to replace them. Most guitarists aren’t cracking their amps open every year to check cap health so inevitably there’s going to be an unexpected failure in a potentially critical moment.
 
The benefit/risk assessment is not always easy. The real question is : is this amp a professional tool ? A mission critical component ? Is there a mission to accomplish to begin with ? A space launch ? A ship rescue ? A world tour ? If the mission is to have fun with vintage amps in a basement, I'd say :
- inspect the caps
- if no bulgin/leak/discoloration and noise while playing, keep them in place.

If you go on a world tour, buy a new amp that will be all new and shiny and easy to replace on site. Now I'll go back to my studio full of vintage amps, the majority of them with original caps and not a single failure so far.
 
Jack Luminous said:
The benefit/risk assessment is not always easy. The real question is : is this amp a professional tool ? A mission critical component ? Is there a mission to accomplish to begin with ? A space launch ? A ship rescue ? A world tour ? If the mission is to have fun with vintage amps in a basement, I'd say :
- inspect the caps
- if no bulgin/leak/discoloration and noise while playing, keep them in place.

If you go on a world tour, buy a new amp that will be all new and shiny and easy to replace on site. Now I'll go back to my studio full of vintage amps, the majority of them with original caps and not a single failure so far.
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All good & nothing wrong with keeping them in to be honest.
Appreciate taking the time to participate in the conversation.
 
Mine looked fine and measured quite well from the outside, and were like this inside:

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Not sure how many of these won’t be dried out at this point, but part of the fun of amps is being able to do whatever you see fit. I don’t think any amp was intended to run with ~50 year old dried out caps in them. If that’s you’re preference, by all means enjoy.
 
MirrorProfiles said:
Mine looked fine and measured quite well from the outside, and were like this inside:

View attachment 58780

Not sure how many of these won’t be dried out at this point, but part of the fun of amps is being able to do whatever you see fit. I don’t think any amp was intended to run with ~50 year old dried out caps in them. If that’s you’re preference, by all means enjoy.
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Man that was just a bad day waiting to come around .. good thing they didn't go "pop" on you.
 
MirrorProfiles said:
Mine looked fine and measured quite well from the outside, and were like this inside:

View attachment 58780

Not sure how many of these won’t be dried out at this point, but part of the fun of amps is being able to do whatever you see fit. I don’t think any amp was intended to run with ~50 year old dried out caps in them. If that’s you’re preference, by all means enjoy.
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Shit man, just throw some duct tape on there and it’s probably good for another couple decades!
 
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