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

*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!

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.

Comments

[ScottH353]

With the switch I have this circuit just joins the to outputs to the input so the outputs are both on no matter where the switch is. I had to leave off the jumper wires on the switch to get it to work.

[ttrat]

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

[dave_b]

For anyone reading this, yes they will work. Just ignore the "ring" connection.

[steve.honest.5]

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

cheers

[dave_b]

Adding a 1meg resistor across the input can help. The thump is typically caused by a DC offset between the guitar and the amp(s) and the resistor can help by directing that DC to ground. If it continues to be an issue, you may want to look at a buffered a/b switch. They're a little more complicated, but it will solve the problem.

[ScottB385]

Not sure what is meant by 'thumps', but if box moves, you could install small, rubber feet. If it is the switch itself, perhaps trying a higher quality( more expensive) switch that are usually smoother action.

[OrionA5]

To stop crackles and other weird sounds. Try using a 3pdt instead of a dpdt. That should stop any noise, when your switching.

[dave_b]

How would that make a difference?

[JasonF188]

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!

[OrionA5]

use a tpdt out you want less noise. On/ off/ on.

[ScottB385]

If you use heat shrink tubing to cover each soldered connection, there is no need to cover whole inside of box with electrical tape. I also like to seal the box lid with a small amount of silicone on the edge.

[Dtb90]

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

Link to the exact one i bought here:

http://www.allelectronics.com/make-a-store/item/pb-176/dpdt-momentary-pushbutton-switch/1.html?extra=a%3A2%3A%7Bi%3A0%3Bs%3A40%3A%2203823345592a403b2f4a37a59384e7ab28f02be1%22%3Bi%3A1%3BN%3B%7D

Thanks.

[ScottB385]

No, you need an On/Off, latching type switch. Check Allied or Switchcraft with those words.

[Filippo Taddei]

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 :)

[ScottB385]

Latching

[J3PPiSH]

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

[thestyrofoampeanut]

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 

[aritoner]

 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]

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]

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!)