VH4 Gain Issue

[insomniac]

Hey all!

I've been having a gain issue with my VH4, making it impossible for me to use it.
Everyone here has always been very helpful, so I'm here to get at it again!

I re-tubed the amp (pre+power) about a year ago.

A few months ago, there was a power outage while I was rehearsing and the amp went off instantly.
I turned it on again after the power came back on and everything sounded great.

I'm not sure the power outage issue is related - but the next few days I noticed a significant gain drop on channels 3 and 4.
I mean, when channel 3's gain knob is all the way up, it sounds like channel 2 mid-gain. There is also a definite lack of the original clarity and definition of the channel.

I can't tell for sure if there is a problem with channels 1 and 2, because I don't play them that often and can't say if they changed their tonality. I think channel 1 still sounds the same, and channel 2 might also be sounding a bit off.

All the fuses are OK, I replaced the power tubes and biased the amp. Still no luck.
The tech who checked out the amp said the preamp tubes seemed fine.

I put the amp aside and went on playing a different amp for a few months.
I turned it on a few days ago and I could swear it was working fine again, but a couple of days later the gain drop was there again.
Maybe I was just imagining it magically sounding good

Any advice?

Thanks a lot!
Ron.

 

[Peter Diezel]

Dear Ron,

please UNPLUG THE AMP, tighten the tube clamps of V3 and replace V3.

Maybe change the topic into "Tube issue"

And ... never trust a tech

Thanks,
Peter

 

[insomniac]

Hey Peter!

As usual, you have been very quick to respond, thank you!

I'll try what you suggested later on today and will get back to you.

Good advice on the tech Never really trusted him..

Ron.