[quote name='bnt' post='254997' date='Aug 5 2008, 01:08 AM']Alternatively, if you fancy a bit of DIY, I've cobbled together a wiring diagram that ought to work. It's passive, but requires a 3-pole dual toggle switch for the A-B / B-A switching, the kind that [url="http://www.wah-wah.co.uk/price4.html"]these guys[/url] have for £ 6.00 each, and I think there are also some on t'Bay.
My diagram is a bit rough, thrown together in PowerPoint, but I hope it looks like something:
[attachment=11601:AB_BAswitch.gif]
(In case it's unclear: the bottom left pin on the 3PDT is connected to both the top right pin and Return 2.)[/quote]
I'd make the bypass switch a DPDT to give true bypass, otherwise you'll have the inputs adding crud to/sucking tone from your signal.
Using a 3PDT works, but you get no indication of what's happening. You'd need an extra pole to work a LED.
Andy