Remote A/B switch

[olddawg]

Sorry but (given what I understand of your application) I still don't see what the problem is with, or what benefit any of these products would have over, a simple AB channel select stomp switch as the last item on your pedalboard?
As the length of cable in the signal path is the same whichever.

I use a variety of amps at different times. The modern one has a standard footswitch for channel switching which I have mounted on my pedal board. I want to use the same setup on other amps. The channel switching would be just external at the amp for the older/simpler amps rather than internal.

[olddawg]

That link is for a unit like Enzo described. It has a jack for a remote footswitch. The A/B stomp section can stay at the amp. It is a relay type unit.

Thanks for pointing that out! I'll check it out. But I think I have the parts to do it. Just a simple a/b box and replace the stomp switch with a SPDT 5V $2 relay and a power supply. Like Enzo said of course.

[olddawg]

If you don't need isolated grounds, this is probably overkill:
Pure A/B+ Remote controlled A/B pedal from Champion Pedals; Allows you to switch between amps while keeping the cable runs short and allowing the flexability of a longer footswitch cable and better tone!

I didn't notice this had the "1/4 inch remote switch" option. It's exactly what I need.