Marshall AVT50 (valvestate 2000) LOW volume, pops, whistles

[MadSKillzMan]

hey guys..scored a 1x12 marshall valvestate 2000 for cheap.

Problem is, volume is rediculously low. There is 0 volume if the gain is turned down, both channels. If i bring gain up to about half way, its usable, but WAY too quiet. Turning the volume to the max results in loud popping, fading in and out of full volume/quiet etc

If you sl owly turn the volume up, when you play you get a whinning sound.

I took it apart and swapped the preamp tube. This stopped all the popping, now it just gets loud/quiet on and off

Also, the clipping LED's do not light, unless it hits its loud burst for a second, then they light right up

I havent tested the line in/out headphones yet

i apprecaite any help guys...i suck at finding the problem...ill go return the favor to those who need some carvin X100b help

[Dave Curtis, dB AudioTech]

hey guys..scored a 1x12 marshall valvestate 2000 for cheap.

Problem is, volume is rediculously low. There is 0 volume if the gain is turned down, both channels. If i bring gain up to about half way, its usable, but WAY too quiet. Turning the volume to the max results in loud popping, fading in and out of full volume/quiet etc

If you sl owly turn the volume up, when you play you get a whinning sound.

I took it apart and swapped the preamp tube. This stopped all the popping, now it just gets loud/quiet on and off

Also, the clipping LED's do not light, unless it hits its loud burst for a second, then they light right up

I havent tested the line in/out headphones yet

i apprecaite any help guys...i suck at finding the problem...ill go return the favor to those who need some carvin X100b help

Just a longshot: get some good contact cleaner (RadShak stocks Caig products) and clean your send/return jacks: short burst of D5 in the jack and stick a plug in and out 3-5 times. Might as well do the rest while you're at it. Don't use it on the tube pins; use Caig GxL for those.

Hope this helps,
-DC

[MadSKillzMan]

hey i shall try that,

just for a heads up, i tried the headphones. They work perfectly, s ounds decent. For some reason today the crackling stopped, i can crank it loud, but it distorts like crazy, and not the good kind, which is making me wonder if its the typical power amp section going.

[Enzo]

If the headphones work OK, then I'd be looking at the headphones jack itself. The cutout contact for the main speaker is there. If that contact does not close well, poor sound results. Measure resistance of all the cutout contacts and clean any dirty ones.