The volume of my speakers going down by itself and going back again in a minute or two

Without any further information I'd say it was demon possession, it could just a curse. Two Hail Marys and 5 Our Fathers for the curse, and get some Holy Water for the possession.. That should cover everything..

Then look at the sticking remote, and change batteries and clean the contacts if need be. Just a thought..

I'll put in a good word before sundown.. It is a day of rest.. :-)

noromance has a point, turn off the lights a see if ALL the valves get dimmer then brighter.

Do you need to bias the valves individually, or is it auto bias?

Are the small valves doing stupid things?

Did you pull the valves and then plug them back in? Stranger thing have happened.. None of this stuff cost anything.

Getting the holy water might cost you a fiver. :-)

Regards