ahh please help

[ZoSo58LP]

hey guys, i have in my inventory a Marshall valvestate 40v model 8040..its a combo amp, and i love how it sounds, except therse a problem..randomly, the sound goes out, distorted or clean...it goes REALLY low, and then comes on randomly, and basically craps out..now i thought maybe its the tube, but then i realzied it dose this on CLEAN channell too, and i read that on valvestates, the tube only affects the distortion..so there goes the theory of the tube..and when i plug my guitar into power amp in, it sounds fine, so my speakers fine..so it leads me to believe that its an actual problem INSIDE the amp? does anyone have any ideas, and do you think i can fix this myself rather than bring it somewhere? thanks!

 

[jonnyc]

Actually I believe the tube is for the clean channel. I have an avt50 and reading the manual the wording makes it sound like the tube is more for the clean than the dirty. Take it in get the tube changed out, they aren't that expensive and if it solves the problem then there you go.

 

[ZoSo58LP]

idk everywhere i looked said its for dist..this amps older luke early 90s soo idk

 

[legionserial]

Same things been happening with my 8080 in the last few days. Except it only goes from quiet to loud and vice versa when i put my coffee mug on top of it. Gonna take it to get checked. I had a feeling it may be the tube...I think the tube is for the preamp (correct me if I'm wrong) so it makes sense that this would be whats causing it.

Still its done pretty well for it to be the first time in 10 years to crap out on me. I just hope its reparable. I don't know what I'd do if I lost it for good. Never had an amp I liked as much. Bought a new amp a few months ago and I still keep going back to this one.

On the upside, its good at night time...I just have to give it a litle tap with my coffee mug and it goes to half volume Sure it aint doing it any good tho lol

 

[seismetr0n]

i had a similiar problem awhile ago with an older solid state amp (ampeg ss150)..
turns out it was due to dirty pots and maybe some bad solder joints
...
i took it to a good repair shop (i also took it to a bad one first, but that was a waste of money)

cost me $150 to have them clean all pots, and touch up all the solder joints...

i would ask around for a good repair shop... i took mine to Abel audio in columbus, OH .. but you're no where near that..

gl