problem with my VH4 - please help...

ajharris1215

ajharris1215

New member
one of my cabinet's input jacks went bad during a show recently, so i unknowingly played my VH4 with a bad load for about 45 minutes. after fixing the cab, the amp didn't sound right. there was a huge reduction in power, volume, and low end. and there is a nasty break up, sounding almost like static, that i can't get rid of.

i've changed tubes and rebiased twice (originally jj kt77s, then jj 6L6, then sed el34s). checked all the fuses. tested with other guitars, cables, cabinets, etc... nothing seems to remedy the problem.

could this be a bad capacitor? or a problem with an output transformer? what about my preamp tubes?

the volume/power/low end of the amp is less than half of what it was. the other guitarist i play with also uses a vh4, and his sound is crushing mine even though his master/channel volumes are lower by at least 40%. and the ugly static break up pretty much destroys my tone, rendering the amp unplayable.

this is not good because i have lots of shows and important recording sessions coming up. the VH4 is the main weapon in my arsenal of a rig. my whole sound is built around it's power and low end. none of my back up amps come close to what it can do... the point is: HELP!!! i need my VH4 fixed fast!!!

peter, can you tell me what to do? should i call terry at diezel USA in georgia? can they repair the amp? help!
 
I hope that Peter joins us fast, but you could try to turn the hum trimmer a bit (pots facing you, amp flipped, right side:) does it go away?
If yes: replace that with a 100 Ohm trimmer.
 
thanks duesentrieb. i wish it were that simple. i adjust the hum trim pot every time i rebias. the ugly break up occurs when i play, not when idle...

there is a real problem somewhere thats causing a drasic loss of power and volume. honestly, i'm suspecting a capacitor. i've had similar symptoms when caps went bad in other amps. the thing is, those amps were all 25 years old or more.

could running a bad load at stage volume have damaged my OT? would that cause these effects?
 
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