Meet my new break out box (B.O.B.) for electric guitar controls

Finally got around to building a tool that I've needed for a while.  Clients bring me pickups to install in their guitars that often lack markings and defy identification.  Said objects are frequently accompanied by requests for non-standard wiring.  I can figure out the resistance and magnetic polarity with other tools but this allows me to do a few things beyond that:

1. I can prototype the wiring and verify proper electrical phasing using micro clip jumpers - with the pickups in the guitar

2. I can try different tone capacitor values

3. I can try different potentiometer values for mixed (single, humbucker) pickup types

4. I can demo pickup wiring combinations for customers who aren't exactly sure what they want - using their guitar and pickups.

Thoughts and comments welcome!

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I think that it is a 'cool tool'.....something I may or may not use..but something to be proud of, since you built it! Congats!!

Any plans available? Or are you going into production??



Thank you - I'll be happy to share the plans in the morning :-)

the knobs all go to eleven!!!!

nice work

OK - you got me - the knobs were an "impulse buy"  (Spinal Tap rules).  Thank you!

Very cool, JR. I've been meaning to put together a tone block myself.


Which components are permanently wired and which aren't?

Are you grounding everything to the case via the output jack?

The pickups are connected to the banana jacks.  Red leads go to the control input.  Ground connections are made to the black leads.  Connections between pickup leads are made using micro-grabber jumpers, which allows experimentation with various combinations.  The case is grounded to the output jack ground.  I tend to use hard grounds for everything else to keep resistance low. 

I wired the cap banks for 250k and 500k separately so that I would have the ability to change the values at a later date. I also considered doing that using a jumper board instead of switches.

Uploaded the schematic.  Will be happy to provide the mechanical drawing package if anyone would like it.


Hi J.R.   ...great project and it should be real useful.  Yep, I'd love to see the mechanical drawing package as well. Thanks!

Drawing files attached.


Nice pro-style work.... thanks for those. 

Agree also! Top-notch stuff.

Thanks, JR....I may give it a go!

Wow, I don't think I'm going to be posting any of my "sketchup" drawing, that for sure. I work on electrics but I might have to build this on general principles.  

Thanks to all for the compliments on the documentation package.  I have been doing Mechanical Design since the 70's and this project was one that warranted 3D modeling to ensure first pass success.  I don't always go this far and often build off rough sketches or design on the fly.  Different tools for different situations.

Glad to share and happy that others will find a use for the design.


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