If I have a 1/4" jack to activate reverb remotely, will any basic single button footswitch work? There's nothing propietry about these, are there? e.g. I don't need to buy a Fender footswitch for a Fender amp?
Stick a guitar cord in the jack. On the other end hold a paperclip or a piece of bare wire across the tip and the shaft on the other side of the insulator ring. If it turns it on and off, all you need is ageneric cheap footswitch. I've also seen guys plug a guitar cord in the jack and the other end into an unpowered effects box and use that as a switch.
I've been jacking with guitar stuff since the 60s so I know a lot of useless stuff that won't help me earn a living but sometimes it helps a younger guy. Good luck.
Another I love is that the older footswitchable amps have an RCA plug. All you need is a 1/4 to RCA adapter from Radio Shack, and bingo your modern 1/4 footswitch can serve as the footswitch for your old amp. That's what I'm currently doing - Solemate Aux Footswitch to Male 1/4 plug to adapter to RCA male plug to amp. Bingo, on/off tremolo to go with the pedal's on/off reverb!