Sound fading...

[ItIsNotSound]

My rack consists of SANSAMP PSA1.1 -> (output) -> BOSS GX700 -> (output) -> ENGL 930/60, guitar is a Schecter omen 7 with Bareknuckle PU's.
Now, the problem is that the sound sometimes "fades" away... And sometimes some electric noise in the background. At the moment, regarding the electric noise, I can't say if it's because of the unstable electricity in this building where I live. I think 2 of the tubes of the ENGL are damaged, could this sound fading caused by the damaged tubes?

 

[Larrikin666]

I'd bet money on power tubes being the issue. I had a similar problem with my ENGL SE before I changed the power tubes. I'd randomly get decreases in my volume when playing. You should pull those two bad tubes out and see if the problem goes away. If not, something else in your chain is bad. You may want to consider getting an Ebtech hum eliminator if you have ground loop to worry about.

 

[ItIsNotSound]

I think so, too.. Is this device suitable for Europe? Would putting a Furman, which I consider in one of the next months beside a better Effects Unit, have the same effect?

Offtopic1: Any ideas where I could get Sunn Speakers (and/or Amps)? Ebay can't be the only place where they appear sometimes...

 

[Tawlks]

I'm having the same problem with my 5150, It's just randomly fading after about 25 minutes of playing give or take, thought I fixed it but at band practice today it went. =/ I turned it off, on again and it worked. What a trooper.

Anyway, everyone at Harmony Central says its preamp tube.. but everone here says power. :S

 

[cradleofflames]

That's probably preamp on both accounts, driver tube most likely. (V2 in a Marshall) In Class A/B amps if one power tube goes it should still work no matter what but at lessened volume and tonal quality.

The Engl should have a driver tube and phase inverter for each side but it could also use different sides of one driver tube for both channels.

 

[ItIsNotSound]

@ topic: I've sold the GX700 multieffects unit, seems like at least that was one part of the problem, the other one was to get the poweramp repaired. at least i hope it'll be gone when all the tubes are changed.