Introduction: How to Make a A/B Box

Picture of How to Make a A/B Box

Learn how to make a amp selector box.

Step 1: Tools and Supplies:

-Soldering iron w/ rosin core solder
-Drill w/ bits
-Phillips Screwdriver
-Electrical tape

1x Project Box
1x DPDT switch
3x 1/4 Mono jacks
and wire.

Step 2: Preparing the Box

Picture of Preparing the Box

*You should go ahead and plug in you soldering iron so it can heat up.

Take you project box (i used a plastic one from radio shack, if you use a metal one you'll need to insulate the inside of the box with electrical tape) and drill a hole on the lid of it.
Then, turn the box on its side and drill another hole for the 1/4 jack.
do the same to the other side.
then, drill a hole on the top of the box for the 3rd 1/4 jack.

Now your box is all ready.

Step 3: Wiring Time!

Picture of Wiring Time!

Now to start the wiring,
Follow this diagram.
*All you have to do is connect the Tip on output A jack to the 1st and 6th prong on the DPDT switch.
*Next, connect the tip of the Input jack to the 3rd prong on the DPDT switch.
*Then, connect the tip on the Output B jack to the 5th and 2nd prongs on the DPDT switch.
*Finally, connect the sleeve of Output A to the sleeve of the Input Jack, And then connect the input sleeve to the sleeve of the Output B jack and finally connect that to the 4th prong on the DPDT switch.

Now, the wirings done :)

Step 4: Finishing Up

Now its time to house the pedal.
After you do that, you can paint the pedal with acrillics or whatever else you want to pant it with.
(if youre going to spray paint it, do it before you house the box)
Then seal the box back up.
Ta-da, youre all done.

  • Time to try out your new A/B box.


JasonF188 (author)2017-05-12

If I wanted to make a stereo version of this box with 2 inputs (L and R) and 4 outputs (LL and RR) would I simply duplicate the internals? Does anyone have a schematic? Would I still use a DPDT switch? Thanks!

Filippo Taddei (author)2017-03-08

Congrats for this great project: I'm an absolute beginner in audio diy and this is one of the first project I'm going to realize.

My question is, is it best to use a latching or a momentary switch? (I'd say latching..) thanks in advance to whoever will answer this :)

Dtb90 (author)2015-04-03

hey buster, i purchased a momentary (on-on) DPDT switch is the correct one to use?

Link to the exact one i bought here:


steve.honest.5 (author)2014-10-22

How do i stop the thumps i get when i switch?


J3PPiSH (author)2010-02-27

can you have 2 guitars insted of 2 amps? :D

that defeats the purpose
and no it wouldnt make a difference
the point is to get two different sounds and two guitars going through the same amp wouldnt sound too different, just a little depending on the pot setup of the guitars 

 i agree it defeats the purpose...but i guess if he had like a les paul and a stratocaster...and you can wire it that way but still i agree it defeats the purpose...but to each his/her own

dhargreave (author)aritoner2011-06-06

Actually, A/B boxes are often used this way because many people who play live have more than one guitar... this way, one guitar can be tuned differently and quickly switched out for a standard tuning guitar without having to unplug, or two guitars with different sounds (yes, guitars do have varying sounds. Two guitars plugged into the same amp won't sound the same unless they're similar guitars). It works both ways for a reason. So yes, you can have 2 guitars instead of two amps (or even a mic and a guitar plugged into an effects board, which you can select between), and no, it doesn't defeat the purpose.

jsegel (author)dhargreave2014-07-30

Yeah, I use A/B boxes on every pedalboard I have ever used for 30 years to switch between guitar and violin using the same effects. You could use them to switch between any instruments you wanted to use the effects chain afterwards with. (Defeats the purpose? That's very short sighted!)

uashada (author)2012-03-13

This wiring diagram is wrong, please check it

mjensen22 (author)uashada2013-07-20

The wiring diagram is correct. There is nothing wrong with it. When A is connected to common, B is connected to ground, and when B is connected to common, A is connected to ground. -- I would have left them as just N/C when not selected, but this works as well.

Eimaj2 (author)2013-03-30

Does it matter how you wire the switch, this is the one I have :
Thanks :)

pilaurox (author)2011-04-13

does this work to plug two guitars into one amp?

if not, is there anything you"d have to change in the wiring to make it for two guitars?

aritoner (author)2010-05-15

 say i wanted to run two different pedal configurations using this A/B box...if i wanted to connect the signal after to have one lead to amp would something similar but just two input jacks wired to one output with no switch do the trick?

-Syrus- (author)aritoner2011-03-28

You are better of with this box then 2 different chains of effects and that connected via a Y-cable to a single input. This way you don't load the signal as much.

so Guitar-> A/B/Y box -> path1 -> Y-cable -> Amp
->path 2

say you make a path 1 clean and path 2 disto, its the same as having a 2 channel amp.

12vox3 (author)2010-10-18

My DPDT switch is an "on-on" switch. Is this the same as you are using?

ttrat (author)2010-09-08

I accidentally bought stereo jacks, would these work as well?

brnofud (author)2010-06-05

This is great! Can you do this with XLR jacks? Could you do this with an XLR input, then two XLR outs on A and just one XLR out on B?

Txiske (author)2009-04-28

Like this project! does it also work as 2 inputs and an output???

Little_Buster (author)Txiske2009-05-09

Yes it can work as two inputs and an output. Cheers, -Buster

exlxaxd (author)Little_Buster2010-05-21

So, you wouldn't need to make any wiring modifications at all? For example, you could just plug your guitar and your keyboard into the jacks labeled (in your diagram) as "Output A" and "Output B," then plug your amp into the jack labeled as "Mono Input" and it'll work in reverse? If that's the case, this would be a really useful item to have around.

Microscope (author)2009-09-11

What about the battery?

Little_Buster (author)Microscope2009-09-14

You dont need a battery. Unless of course you threw some LED's in the mix. As leobsd said, Its more or less "Mechanical" switching.

leobsd (author)Microscope2009-09-12

actually, you don't need a battery in this case because there are no leds on the circuit. You're only switching between the two outputs according to the DPDT state... it's sort of "mechanical" switching,

marcusjc (author)2009-07-22

im sorry but how do u change it from outputs to two inputs, what i wanna do is make a pedal that i can run into the one amp, but plug my lapsteel and my electric piano into.....

jj123 (author)2009-07-05

Yo I built this today and it works alright except the guitar is quite a lot quieter than if I plug it directly into the amp. Awesome project though, well done.

Little_Buster (author)jj1232009-07-05

Check all your solder joints to make sure none of them are cold. Cheers, Buster

jj123 (author)Little_Buster2009-07-06

Yeh they all are as my soldering iron was to week to get it anywhere near melted by heating the component.

Little_Buster (author)jj1232009-07-07

Then thats probably the problem. Just go pick up a cheap one and correct all those joints :] Cheers, Buster

About This Instructable




Bio: Ive been modding and building Guitars/electronics for 3 years. Ive been playing guitar for 8 years and piano for 9. PM me if you ... More »
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