Sunday, December 4, 2011

Simple guitar A/B switch

A couple of weeks ago my brother, my cousin and I attended the annual Muzikanten dag (musicians day) event in the AB in Brussels.  On that day you can participate in numerous music workshops, demo's, training sessions ... you name it.
I really enjoyed the day and my cousin got inspired by the 'wall of sound' workshop by the Belgian band The sore losers.  They had some really good tips on how to create your guitar sound, and one of the key elements in their setup was a simple A/B switch.  They use the A/B switch to switch between 2 amps.  This is a very simple -but clever- way to get a punchy solo sound : hit a button, second amp switches on > instant boost.
The trick is to set the second amp relatively 'clean' so you don't loose the 'punch' of your sound.

A couple of days later my cousin asked me if i could build such a switch, and this is the result :

Rather sexy I think !

The circuit is really simple and based on a number of designs that are available on the web (just google "guitar a b switch diy").
The box has 1 in and 2 outs (A and B), it has 3 switches (A/B, A+B, MUTE) and is completely passive. This was an absolute requirement for my cousin as he hates batteries (don't we all?) and he has a love/hate relationship with AC adaptors: they tend to start smoking after a while  ;-P
Being passive of course means that there are no indication LED's on the box.

The circuit looks like this:

As you can see it is really simple so it's real easy to translate this to a wiring diagram:

The box turned out pretty well ... i might just make one for myself one day !


  1. heel proper, nu nog testen :)

  2. Looks good! No grounding or phase issues? And where did you get the metal casing from?



  3. Hey Jeremy, no issues so far, but i have only tested it with a mono (line level) input signal and connected my 2 active monitors to the A and B out.
    Seemed to work very well, but like Stijn wrote : "looks nice, now let's test it"
    So until then, i'll just shut up ;-)

  4. update : yesterday we tested the switch (with guitar + 2 amps + some other stomp-boxes) and it works great :-)