ac24

hey great forum here! i picked up a used dsl100 for a great price. my first marshall head...great amp. but i had a couple questions when i take it off standby ill get almost like a white noise with an occasional slight crack or pop for about the first minute then it goes away. any ideas? thanks alot!

stryker59

congrats on the new amp and welcome!!!! not sure of the problem on your amp but its probably tube related....change em out and that hopefully will take care of it!

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ac24

thats what i figured as well but the guy i bought it from said he put new all new ones in about a week before i got it

stryker59

hmmmmm perhaps adwex has an idea. Adwex?

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Brett Blackmore

Hi,

you need to switch the amp on and then wait 2 minutes for the tubes to get warm. Then
when you then switch off the standby the tubes power up to performance level. Sometimes they cracle and pop, but it is not a true fault. The problem is that one thinks it is a fault because it appears to be acting like a faulty amp. I had a Peavey which popped at start up and then I had expensive ceramic bases inserted and it popped even more. It should go away after 10 seconds, if not then you need a technician.

Q. did the owner re-bias it as well? maybe the tubes are ok but the amp is not quite biased correctly.

RiverRatt

That's either a preamp tube going bad or you're not leaving the amp on standby long enough. I know that sound you're describing all too well. If you have a known good preamp tube, swap it around until the noise goes away.

Adwex

Wish I could help, but I have no experience or knowledge of the DSL's. As others have suggested, I would do the usual easiest thing first....look for a bad preamp tube. Just because the previous owner replaced them, don't assume they're good. Tubes are like light bulbs (but more complicated), they are somewhat delicate, and don't last forever. Before you buy a new one, just try swapping the tubes around in different positions. Each "preamp" tube serves a different purpose...a tube that doesn't work well in the first position might be ok in the 2nd or 3rd postion, etc.

It could also be something more involved, JCM 2000's are not simple amps.

I'd also clean all input/output jacks, and tube socket/pins with contact cleaner.

Try this:
DeoxIT®, #D100L-2C

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