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.. :-)

Your new to you 20 year old pre and power amp might need a tech check.

I had the same thing happen. Then I realized the dog was stepping on the remote. All 7 pounds of him.