signs of a problem in an amp

[gizzi]

i recently bought an engl tube preamp (E530)  and it sounded awesome. after the first few days, i replaced the stock tubes and put in JJ's. sounded awesome with them too. (but a little better IMO) anyway, one day i turned the amp on it didnt sound like it used to. sounded kinda weak and flabby/a little on the metallic side. so, i replaced the tubes thinking that might be the problem and it sounded great like it used to for like the first half hour and then started sounding bad again. i sent back the amp to engl-amps usa's tech and he said there was nothing wrong with it. any idea why the sound could have changed? possibly low filament heater voltage? thanks, garrett

[JimRayden]

The sound of your gear depends largely on your mood. Sometimes you're playing your dream tone, other times you're cursing your gear for sounding buzzy and the knobs for having no effect. It's all in your mind.

And I can't see a reason for a low filament voltage.

Hmm, a possibility would be the change of mains voltage but it shouln'd affect the sound that much.

-----------
Jimbo

[petemoore]

i recently bought an engl tube preamp (E530)  and it sounded awesome. after the first few days, i replaced the stock tubes and put in JJ's. sounded awesome with them too. (but a little better IMO) anyway, one day i turned the amp on it didnt sound like it used to. sounded kinda weak and flabby/a little on the metallic side. so, i replaced the tubes thinking that might be the problem and it sounded great like it used to for like the first half hour and then started sounding bad again. i sent back the amp to engl-amps usa's tech and he said there was nothing wrong with it. any idea why the sound could have changed? possibly low filament heater voltage? thanks, garrett

"Look outside'...could be...'anythings' beside the unit.

[Connoisseur of Distortion]

if there's a cathode bias adjust, it might simply be poorly biased. i dunno. i've just heard similar problems...

[gizzi]

thanks guys...i was also thinking it could possibly be the mains voltage thats coming into the amp from the wall. would a low wall voltage cause a change in tone? like lets say, a drop of maybe 15 volts or so? do power conditioners (like furman) eventually start to lose something, like the ability to condition voltages? thanks, garrett

[JimRayden]

No, I don't think it's the mains voltage. Normally it doesn't change enough to make amps sound bad. Unless you've got a generator chugging in your basement. 

----------
Jimbo