Marshall dsl 100 help

[jake_xms3_punk]

I recently changed the valves in my amp and it worked fine for a bit but then one valve started red plating. I tried to rebias and got it running cooler but now I can't get it higher then say 40mv on that side. Do you think it's a bad tube screwing up my bias setting? Should I take it out along with one from the other set and run at 50 watts and about 40mv each side? just until I can get new valves? I have a few gigs lined up this week and wont have time to take it to a tech. Any advice would be appreciated! Cheers

 

[metalspider]

Re: Marshall dsl 100 help

sometimes you just happen to get a dud,get it replaced by the shop you bought it from.

 

[Chickenwings]

Re: Marshall dsl 100 help

do all the old tubes work ok?

 

[glassman]

Re: Marshall dsl 100 help

Sounds like you may have a bad tube in the new set you just bought...it happens. If the old tubes are still functioning, drop em in and rock em. The bias setting on the 100 watt amps is the current of 2 tubes at once so your 40mA bias is actually 20mA per tube...pretty low...and an indication of a tube problem. Stick the old set in and set them at 90mA like the owner's manual suggests and enjoy. Chances are you replaced them way earlier than they needed to be anyway...most people do. Usually a "touch up" of the bias is all that's required to bring it back to life.

 

[jake_xms3_punk]

Re: Marshall dsl 100 help

Thanks guys. I threw the old tubes away. The amp was blowing fuses and crackling until finally no sound came out at all so I assumed the valves needed changing. Also the bias pot on the side that was red plating has always been iffy, its loose and I had to push hard at an angle with the screwdriver to get it to work. Could that have something to do with it?