#1
Cranked the Marshall DSL401 today master at about 9, OD1 at about 5, Les Paul volume from 3-10. Keep in mind this is the first time I have pushed it since I bought it used a few months ago. Between songs when i would put my fingers over the strings it would pop. For instance if you put your fingers on the strings to do a harmonic not pushing down on the frets anywhere on the guitar I would get popping. This amp has never done this at lower volume. Any ideas. And yes I did try searching other posts but could not find anything this specific. Furthermore, if the tubes are determinded to be at fault are they the preamp tubes or the power tubes and if so can I order new tubes and replace it myself with ease and without destroying my amp. Thank you fellow UG'ers for always helping.
Gibson 58 VOS, Gibson Rich Robinson ES-335, Fender Strat, Fender RoadWorn 50's Tele, Gibson LP Jr Special

Marshall JTM45, Fender BJR NOS
#2
Tube replacement is considered standard maintenance. it sounds like it may be a preamp tube that has gone slightly microphonic.

Popping can also happend it your strings touch the pickup magnets...your pickups wouldn't happen to be way to close?
#3
no the pickups on the guitar are fine.....is there a way to find out if the tubes have gone microphonic? i heard lightly tapping on the tube when the amp is on with the pencil could help me determine it. if i do change tubes would i want to bring it to a tech to bias it considering i have no experience with biasing amps.
Gibson 58 VOS, Gibson Rich Robinson ES-335, Fender Strat, Fender RoadWorn 50's Tele, Gibson LP Jr Special

Marshall JTM45, Fender BJR NOS
#4
Well, depends....if it is a preamp problem, then these is no biasing needed. The easiest way to fix this...swap one tube at a time and see if the problem goes away...if so, there is your bad tube. Here, only the one tube need to be swapped, for anything of your choice.

If your problem still persists, then it's the power tubes. Here, you'll need to replace all of them, as they need to be matched. Then, the amp needs to be rebiased.
#5
sounds great i will look into this. i really appreciate your help
Gibson 58 VOS, Gibson Rich Robinson ES-335, Fender Strat, Fender RoadWorn 50's Tele, Gibson LP Jr Special

Marshall JTM45, Fender BJR NOS
#6
This may not help but when you used it cranked was the amp being played in the usual place? Just I moved mine to a back room of the house to jam and the thing popped like mad in the few seconds it was on. Turned out the powerpoint in the room was dodgy, probably a poor ground. That was the first and last time I use my amp without a surge protected powerboard too. Anyway just my 2 cents.
#7
actually it was moved to my garage which doesnt look like it would have the best electrical
Gibson 58 VOS, Gibson Rich Robinson ES-335, Fender Strat, Fender RoadWorn 50's Tele, Gibson LP Jr Special

Marshall JTM45, Fender BJR NOS