DIY A/B Switch Box

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White_Rabbit

New member
Ok, I wanna build a really small, idiotically simple A/B switch box to switch between keyboard/theremin and Guitar, and I figured with my absolute lack of knowlege to do with these sorts of things, that I could build it using 3 x 6.5mm input sockets and a SPDT switch, hooked up with two of the plugs going in on one side (the "input points) and the 3rd plug on the other side, sort like the picture below, except inside a small container (I have an empty mints container made of metal that is the perfect size). Also, the second "prong" on each of those plugs is the ground, yes? So should I just solder them to the tin or a common point?

ABSwitchBox.jpg


Am I missing something here, or will this bare-minimum approach work? Should I be adding some capacitors or something for some reason, such as to level out the voltages or somesuch? Those A/B pedals that Boss and such make surely have more to them than this...?

PS: Sorry if this isn't the right forum, but I figured it sort of applied, and this area gets plenty of hits, which means more chance of someone with some knowledge being albe to help me :D
 
Last edited:
White_Rabbit said:
Ok, I wanna build a really small, idiotically simple A/B switch box to switch between keyboard/theremin and Guitar, and I figured with my absolute lack of knowlege to do with these sorts of things, that I could build it using 3 x 6.5mm input sockets and a SPDT switch, hooked up with two of the plugs going in on one side (the "input points) and the 3rd plug on the other side, sort like the picture below, except inside a small container (I have an empty mints container made of metal that is the perfect size). Also, the second "prong" on each of those plugs is the ground, yes? So should I just solder them to the tin or a common point?

ABSwitchBox.jpg


Am I missing something here, or will this bare-minimum approach work? Should I be adding some capacitors or something for some reason, such as to level out the voltages or somesuch? Those A/B pedals that Boss and such make surely have more to them than this...?

PS: Sorry if this isn't the right forum, but I figured it sort of applied, and this area gets plenty of hits, which means more chance of someone with some knowledge being albe to help me :D
Click to expand...

That is basically the same thing I did and it works fine. I didn't bother to ground it as the nuts that tighten the switch and the jacks are all in contact with the tin and so grounded through the whole system. I have modified mine to have a "thru" jack as well. So I can have the signal going guitar to one non switchable amp and the other lead going to another amp with channel switching.
 
From looking at the picture, it appears that you may have the grounding lugs soldered to the switch instead of the hot pins. Look at the jack carefully and be sure that your switch is connected to the solder lugs that are connected to the part of the jack that grabs the tip of the plug. If the metal box is conductive (not painted), then connecting the grounding lugs is not necessary.
 
Oh, yeah, lol, thanks, the diagram was simply a mockup to show the general layout, I didn't even check which point was the ground and which the intrument signal joint, but thanks for the heads-up none the less!
 
So you're running your guitar and your keyboard rig through the same amp? Are you using a modeler with your guitar then through a full range PA? Just curious if you're running both rigs through a guitar amp.
 
Actually, I'm the drummer in our band, but the keyboard is an old farfisa 1970's keyboard I picked up for $45, and so we occiaisionally run it through a guitar amp if we're doing some sort of psychedelic jam, and as for the guitar itself, it'll mostly just be used for effects (probably done by our vocalist), as we already have two guitars in the band, so no, no modeller. Mostly we just experiment with anything and everything, hence the weird setup.
 
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