Adding an extra output and bypass to an ABY

[Jimi W]

Hi,

I built an ABY pedal for a friend using the following layout

http://aronnelson.com/gallery/TheBigMan-Layouts/abyled

Works a treat and there's no ground issues with the 2 amps he's using. He now wants to add a 3rd amp to his setup ( I know!)

This third amp will be used seperate to the aby box, e.g he may switch it on while he's using any combinations of the other 2 amps (a on its own or b on its own or a+b) but he'd like it in the same enclosure so all the amp switching is done in one place.

What would be the best way to add the 3rd amp?

Do I add a switch just after the input jack tip before it reaches the a or b switch? If so what would be the best way to wire it so there are no ground issues with the 3rd amp? I thought I'd got my head around switching/input grounding of true bypass wiring etc but the fact that the input signal will always need to flow through this new switch to the original aby circuit is confusing me!

Any help would be appreciated.

Cheers Jimi