I can't believe I'm asking this... (A/B box questions)

[irmcdermott]

Such a noob question. I just don't have a diagram in front of me....

Can you use any A/B box to be used as either 1 input to 2 outputs or 2 inputs to 1 output? Or do you have to wire it differently? Same question for an A/B/Y box?

I've never built on and was just requested to build 2 of them.

Friends band has a violin/guitar player. He wants 1 pedal on the front end to switch between his guitar and violin into his pedal board.... He also uses 2 amps and wants to come out of his pedal board to switch between the amps.

So my first thought is an A/B on the front for his guitar/violin and an A/B/Y to his amps. Thought? Direction?

[oldhousescott]

For the front end, a simple passive A/B box is fine. For the output to two amps, you might want to get a little fancier. If you send a signal cable to two amps without lifting the ground on one of them, you might get a ground-loop induced hum in the amps. To prevent that, you can make an A/B(/Y) box with an isolation transformer feeding one of the outputs.

[irmcdermott]

so then the A/B box does work both ways (as far as inputs and outputs are reversible).

and for the A/B/Y box with the isolation transformer, have a link to a project? isn't there one on R.G.'s site (geofex.com). i think there is.

[oldhousescott]

Yes, a simple passive A/B will work both ways. Active A/Bs with buffers will likely have a switch to change from 1->2 to 2->1. As you're the one building it, I assume you'll be doing a simple passive A/B.

For the one with the isolation transformer, I was thinking there was a diagram on Weber's site, but I couldn't find one. You may be right about it being on RGK's site, or perhaps on Jack Orman's site. Jensen transformers has an application note for a 1->2 guitar interface, but without the switch. You should be able to easily figure out how to add one to that diagram.

[irmcdermott]

Awesome. Would the BAJA Silent Selector project over at FSB be a good option for the A/B/Y?

http://freestompboxes.org/viewtopic.php?f=13&t=2564

i look to that one because it's got a pcb i can etch and build. thanks for your help on this!