#1
I've had my Marshall JCM2000 DSL 401, for just over a year but recently it has seemed to have lost a bit of it's power. It doesn't feel as -gainy- as it used to. Every now and again it seems to kick in for about 2 minutes before dulling down again, is this a normal problem?

Could it be a problem with the tubes? If so, which ones will I need?
#2
Sounds like some preamp tubes to me.

JJ 12AX7's are what I'd recommend here, but I'd wait for someone more knowledgeable then I am to come in, just in case I'm wrong!
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#3
Try your spare tubes, both pre and power. You do have spare tubes, right?
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#4
Quote by tubetime86
Try your spare tubes, both pre and power. You do have spare tubes, right?

not that I am aware of, do spare tubes usually come provided or?
#5
Quote by messupp
not that I am aware of, do spare tubes usually come provided or?

Nope, but most people realize that eventually the day will come that they need new ones so having spares just makes sense.

On top of that, tubes generally don't just fail... They do funny things that mimic larger issues with the amp. The only way to diagnose whether or not it's just a tube issue is having spares... Such as in your situation. If you had tubes you'd throw them in and likely the issue would be gone. With no tubes to try out you're left guessing.

Here's the real crappy part though; now you need new tubes (presumably) so when you replace them you still won't have spares, because the old ones are (presumably) shot... So what I'm saying is now you need to buy two sets of tubes.

If you want to do the bare minimum, buy a 12AX7 and try it out in each of the positions for preamp tubes. It is likely only one preamp tube is blown.
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Unless its electronic drums.

BURN THE WITCH!!!!!
Last edited by tubetime86 at Aug 28, 2014,
#6
Quote by tubetime86
Nope, but most people realize that eventually the day will come that they need new ones so having spares just makes sense.

On top of that, tubes generally don't just fail... They do funny things that mimic larger issues with the amp. The only way to diagnose whether or not it's just a tube issue is having spares... Such as in your situation. If you had tubes you'd throw them in and likely the issue would be gone. With no tubes to try out you're left guessing.

Here's the real crappy part though; now you need new tubes (presumably) so when you replace them you still won't have spares, because the old ones are (presumably) shot... So what I'm saying is now you need to buy two sets of tubes.

If you want to do the bare minimum, buy a 12AX7 and try it out in each of the positions for preamp tubes. It is likely only one preamp tube is blown.


Thank you very much, will order now!
#7
what year is the amp?

the reason is that some of them had rectifiers that overheated, and you would need something with better heatsink to keep the temp down.

i cant remember if it was before 2003 models or after???

_________

i should have said one more thing. if the rectifier is overheating, its not the problem you have now, but may as well get it done at the same time. your problem is tubes.
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Last edited by trashedlostfdup at Aug 29, 2014,
#8
After 2003, they upgraded the rectifier. That manifests as overheating. This sounds like a tube.
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#9
Quote by Cathbard
After 2003, they upgraded the rectifier. That manifests as overheating. This sounds like a tube.


thanks cath

yea i know it does sound like a tube, but may as well know a problem that may arise in the future. at least he will know.
WTLT 2014 GG&A

Quote by andersondb7
alright "king of the guitar forum"


Quote by trashedlostfdup
nope i am "GOD of the guitar forum" i think that fits me better.


Quote by andersondb7
youre just being a jerk man.



****** NEW NEW NEW!
2017-07-07 2017-07-07 Update and a Chat On Noise Constraints *** NEW FRIDAY 7/7
2017-04-13 RUN AWAY from COMPUTERS!!! TCE? RANT ALERT!!!
2017-03-02 - Guitar Philosophy 1001- Be Prepared For the Situation (Thursday 2017-03-02)
2017-02-21 How to Hot-Rod the Hell of your Stratocaster for $50! (Tuesday 2017-2-21)
Resentments and Rambling from a Guitar Junkie
---> http://trashedengineering.blogspot.com/