Problem with Single Rectifier volume drop

[jgcable]

I have a Single Rectifier Series 2 5 mode head. It has been dead reliable for me for the last 3 years with no issues at all. Just recently I noticed that I will get a slight momentary volume drop when I am playing it. The drop is probably about 6 db and it lasts for about a half a second. If I am not playing it and I leave it on the red channel (where I can actually hear the amp running) I can actually hear the amp drop. The best way to describe it is when my dehumidifier kicks on it will cause the amp to do the same thing. I tried cleaning the jacks and pots and I tried running something in the loop or nothing in the loop. Doesn't seem to make a difference. One thing is it won't start acting up until its been on for at least 10 minutes. It may have always done this but I only use the amp live so I would never hear such a slight drop in volume so quickly. I have been using it for recording at home and this is where I noticed it. Does this sound like a tube change? I haven't changed the tubes in about 2 years.

 

[deeman]

So does this only happen when the dehumidifier kicks on?

 

[jgcable]

So does this only happen when the dehumidifier kicks on?

No, I was just using that as an example of the drop off.

 

[bendo]

Sounds like it's time for a new set of Power Tubes. Volume drops after the amp has warmed up are the first sign of power tube failure.

 

[tele twister]

Mesa says 10-15 hours a week at moderate level, power tubes last about 1-1.5 years.
Check out the Mesa store to learn more about it.
I got a pair of EL34s and 6L6s from there to see which I like better. (I like the 6L6s)