New Rectoverb 25 loses gain as it warms up. Any ideas?

[guitarman3001]

Hi, I recently bought a Rectoverb 25 combo and after playing several gigs with it I've noticed that as the amp warms up it loses gain and as the night goes on I have to turn the gain up in order to keep the same amount of distortion as I started with. It does this on both channels. It's obviously more noticeable on the distortion channel but it does the same thing on the clean channel too. It's more noticeable on that channel when it's set to pushed mode.

I currently own and have owned countless other tube amps and have never experienced anything like this with any of them.

Anyone have any guesses as to what may be causing this? Could it be a preamp tube?

And another thing I've noticed is that the front faceplate gets extremely hot. Pretty much too hot to touch comfortably. I know some tube amps run very hot so maybe this is normal for this amp but maybe it could be related to the loss of gain?

 

[dearco19]

Could be tube issues, try first by re-tubing your amp or change the preamp tubes between them. I also have noticed that the front faceplate gets very hot but I never have experienced the main issue.

 

[deeman]

You could try swapping out one preamp tube at a time with a known good tube and see if you can find the problem that way. Sometimes you get a bad tube off the bat that needs replacement.

 

[elvis]

The tubes tend to hit max temp early. I believe that over time the board and chassis components heat up. I suspect either a bad connection/solder joint or a bad component (maybe a resistor that changes value as it heats up).

I'd swap tubes, but probably wind up sending it for service. Hope it's just a tube!