Marshall DSL 2000 issue

  • Thread starter Thread starter Nickelbagn
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Nickelbagn

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I love my marahsall DSL 2000 but I keep having an issue of it dropping out in volume. It sounds like a preamp thing and I took it to get fixed once but it has happened again and I honestly don’t understand the explanation the tech gave me. Is this a common issue for this head?
 
Ya, and do you know was done the first time to fix it?
 
I’ll be honest. He rattled off a bunch of technical stuff that I couldn’t follow about the power section being faulty and unreliable with these heads. He said he’d fix it but it would just happen again when I pushed it.
 
I brought it home and it worked fine until it travelled to a gig and I brought it back. When I turned it up, it would play fine for 10 seconds and then drop in volume for 5 seconds. It just wouldn’t hold full volume any more.
 
ZEN Amps said:
They pre-2003 have a design flaw - that could be your issue, it could be something else. Your tech sounds like he already knows, so we can't do better than just asking him to clarify it for you.

https://valvetubeguitaramps.com/marshall-jcm2000-bias-drift/
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That's great somebody made this. I replaced the whole board in a friends DSL...still did it. Almost makes me want to keep my eyes peeled for a cheap DSL, they can sound pretty good imo.
 
Nickelbagn said:
I’ll be honest. He rattled off a bunch of technical stuff that I couldn’t follow about the power section being faulty and unreliable with these heads. He said he’d fix it but it would just happen again when I pushed it.
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Yea. These heads are garbage. You can order the entire power section board, but you’re getting the same board instead of them providing an upgraded board
 
scottosan said:
Yea. These heads are garbage. You can order the entire power section board, but you’re getting the same board instead of them providing an upgraded board
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That’s pretty much what the tech said. He even asked if I wanted to pay to have it fixed or just sell him the head for parts because it was going to happen again. I needed it for a gig so I had him fix it.
 
SpiderWars said:
That's great somebody made this. I replaced the whole board in a friends DSL...still did it. Almost makes me want to keep my eyes peeled for a cheap DSL, they can sound pretty good imo.
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Thanks for the great info. I guess I was mostly looking to see how many people have had the same issue and if I should start looking for a similar sounding replacement.
 
Nickelbagn said:
Thanks for the great info. I guess I was mostly looking to see how many people have had the same issue and if I should start looking for a similar sounding replacement.
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Its very common, I'd fix it myself but for those that would have to pay a tech for it, that depends how much you like it.
 
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Ive had a 2005 & still have a 2008 JCM-2000 DSL-100 and ive never had an issue with either.
They fixed the boards in early 2000's.
Not all garbage. Industry standard for over 25 years including Gary Moore & Jeff Beck and many more.
FWIW ive seen tons of problems with the Vietnam Marshalls too, tho some of that likely user error which is true with any amp.
 
I know a good fix. No custom board needed.

I’d love to buy an early one for a good price if someone’s selling.
 
glpg80 said:
I know a good fix. No custom board needed.

I’d love to buy an early one for a good price if someone’s selling.
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Are you talking about cutting the trace and adding a wire straight to the tube pin? I considered that too.
 
SpiderWars said:
Are you talking about cutting the trace and adding a wire straight to the tube pin? I considered that too.
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What's the issue with the trace?
Intermittent cracks or not large enough for the current?
 
Donnie B. said:
What's the issue with the trace?
Intermittent cracks or not large enough for the current?
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The screen and grid pins on the power tubes are adjacent (4 and 5). Those traces are too close and the board gets a little conductive when hot. So when it gets hot the high positive screen voltage pulls the negative bias voltage towards positive (less negative) and the tubes just run hotter and hotter until it shuts down. So the fix is to not use both traces, one of them gets cut and a wire is added in it's place.
 
SpiderWars said:
Are you talking about cutting the trace and adding a wire straight to the tube pin? I considered that too.
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Yep, convert the bias to flying lead style and cut the traces right off the filter caps after the reverse biased diode.

You don’t need a custom freaking board. It’s a simple problem with a simple fix but you have to know what you’re doing.
 
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