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Building an A/B switcher

gitlvr
November 30th, 2011, 11:29 PM
Hi guys.
I'd like to build an A/B switch box, so that I can plug two guitars into the box, run a cable to my amp, and use the switch to "switch between them.
Seems like this would be fairly simple to build. A switch, and 3 1/4" jacks.
Are there any plans available for this?

FenderLover
December 1st, 2011, 12:17 PM
It's the same as an A-B switch used for one guitar and two amps, just turned around. There are many A-B schematics that are pretty good. I like the Fulltone one.
You can get fancy and add separate preamps with separate preset volume settings for each guitar as long as you're rolling your own. Just a thought.

gitlvr
December 1st, 2011, 01:34 PM
Thanks, FenderLover!

BenM
December 4th, 2011, 10:30 PM
Hey FenderLover, I am trying to figure out this stuff too. Looking at your schematic, I am wondering why the section of the switch labeled Sw1b is necessary. It seems to me that if you left this section out it would still work, even if the unused half of the circuit is not grounded. Is this section there to make this "true bypass" switching? Thanks for your help.

FenderLover
December 5th, 2011, 12:30 PM
S1B grounds the input of effect A when B is selected, and grounds the input of effect B when A is selected.

It is not always necessary because the input circuit of the effects are usually ground referenced, but it's a good idea.

Like I posted in your other thread, there is nothing "True Bypass" about an A-B or A-B-Y switch. In this case, the signal is routed to one output or the other. "Bypass" is not actually the function of the circuit, it is a switch. The switch is always in the circuit, but don't sweat it - in an actual "True Bypass" circuit there are TWO switches always in the circuit.

BenM
December 5th, 2011, 01:25 PM
Thanks, FenderLover, I think I get it now, I am just a little slow on the up-take. :)