#1
I recently purchased a DSL50. Played it for a few hours, couldn't have been happier with the tone. I know it needs a re-tube and I have already ordered some new tubes. However, a problem has been occurring recently that I can't be certain is the result of a bad tube.

Sometimes, whether I am plugged into the amp or not, the amp will make a sound as if I pulled the cable out of the jack on my guitar. Its a Pop...crackle...squeeeeeelll. Then another pop as if I plugged the cable back into the guitar and the problem goes away.

Think this is just a bad tube?
#2
EDIT: Just read your post again, my first post was a massive fail lol.
Check have a look at your tubes when the amp is on to see if any of them are glowing massively dimmer than the others. Saying that though it could be an issue with the circuit board, I had a similar problem a few years ago and the circuit board blew after a very short period of time with the problem, cost a fair bit to fix. Nowadays I say, if in doubt take it to a tech.
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Last edited by SurfinWithSatch at Dec 27, 2011,
#3
Its not the guitar, I have a few different amps in the house right now that I tested the guitar/cable/pedals through. I have isolated the issue to the amplifier itself.
#4
Quote by SurfinWithSatch
EDIT: Just read your post again, my first post was a massive fail lol.
Check have a look at your tubes when the amp is on to see if any of them are glowing massively dimmer than the others. Saying that though it could be an issue with the circuit board, I had a similar problem a few years ago and the circuit board blew after a very short period of time with the problem, cost a fair bit to fix. Nowadays I say, if in doubt take it to a tech.


If I absolutely have to I will, however the nearest tech is a long way away and my wallet is light these days. I'd like to get some opinions on what the problem could be/tests that I could perform so I know whether or not taking it to a tech is necessary.
#5
It could very well just be one of the jacks on your amp. give them a good cleaning and if it still happens open it up and check for weak solder joints. thats where i would start anyways. others may have better suggestions tho as i am fairly new with tube amps myself.
#6
Contact cleaner? Is that what I should use? Also another DSL50 related question. Checked the bias on the tubes that were in there. They were running at 50mv. Marshall recommends 45mv. I set it to 40mv a half hour ago and let the amp sit on with the guitar unplugged...came back it now reads 46mv. Why is it climbing on its own? I am confused.
#7
The bias current will change as it warms up properly. It will settle down after a while. Worn out valves can drift around a fair bit too.

Any contact cleaner will do, Deoxit is a good one. When cleaning sockets use a plug as an applicator. ie. spray some liberally on a plug and work it in and out of the socket a few times.
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#8
Quote by Cathbard
The bias current will change as it warms up properly. It will settle down after a while. Worn out valves can drift around a fair bit too.

Any contact cleaner will do, Deoxit is a good one. When cleaning sockets use a plug as an applicator. ie. spray some liberally on a plug and work it in and out of the socket a few times.


I will do that. Thank you Cathbard. I will let you guys know how the amp fairs after I clean the amp input and pop in the new tubes. I'm hoping the issue is simply tube related.
#9
So I popped in the new tubes, biased the amp, and cleaned her all out. Tone is FANTASTIC. I can't believe how much of a difference a fresh set of tubes made.

The amp sounded thin and fizzy before, but not anymore. NAD coming when I can get some quality pics and spend some time dialing her in now that shes running at max stock potential.