Wiring help: accidental kill-switch!

Pickups, magnets, microphones, amps, speakers, cabs, whatever...
Post Reply
Jason Rodgers
Posts: 1554
Joined: Fri Jan 06, 2012 4:05 pm
Location: Portland, OR

Wiring help: accidental kill-switch!

Post by Jason Rodgers »

On my #4, the black maple with purple fretboard, I used a push/pull pot wired as a tone control with bypass: pushed down is bypassed, pulled up is tone. Here is the diagram. (For the life of me, I can't remember where I found the original online, and searching doesn't bring up anything that looks familiar.)
Tone bypass schematic.jpg
And in the guitar.
Tone bypass real.JPG
It works, except for one little funny problem... when the pot is pushed down and rotated fully clockwise, the signal cuts. Nothing.

There's a good possibility that I simply drew this diagram wrong. Actually, since most of the diagrams online are of a push tone, pull bypass, that's a rather high probability.

Anybody see anything that looks obviously wrong? Thanks!
-Ruining perfectly good wood, one day at a time.
User avatar
Dan Smith
Posts: 346
Joined: Mon May 18, 2015 9:33 pm
Location: Texas

Re: Wiring help: accidental kill-switch!

Post by Dan Smith »

Remove wire on pot terminal 3 and remove the ground wire to the switch.
Ever-body was kung fu fight-in,
Them kids was fast as light-nin.
Jason Rodgers
Posts: 1554
Joined: Fri Jan 06, 2012 4:05 pm
Location: Portland, OR

Re: Wiring help: accidental kill-switch!

Post by Jason Rodgers »

Dan Smith wrote:Remove wire on pot terminal 3 and remove the ground wire to the switch.
Thanks, Dan. After posting this question, I went back out to the shop to poke around a little more. I got to thinking about why it would be one direction of rotation that caused the signal cut and not the other. With pot terminals 1 and 3 wired symmetrically to the middle push/pull tabs, what's different in the down position? That one ground on the right: when the wiper is turned fully clockwise, the whole signal grounds out. (This is a pretty elementary "lightbulb" moment, but my understanding of the signal path through electronics is pretty elementary. These mistakes help me learn!)

I clipped that ground, and problem solved. What would be a glaringly obvious error to anyone with more experience was something I simply overlooked.

But you suggested I remove another wire, Dan. It works now - pushed bypasses the cap, and pulled operates as a tone control - so what else would removing the wire on terminal 3 do? Is it just redundant? Can you walk me through this? I appreciate your time and patience.
-Ruining perfectly good wood, one day at a time.
User avatar
Mark Swanson
Posts: 1991
Joined: Thu Jan 05, 2012 11:11 am
Location: Grand Rapids, Michigan USA
Contact:

Re: Wiring help: accidental kill-switch!

Post by Mark Swanson »

As long as you removed it from the pot, that's all you need to do. It doesn't matter at all if the switch has grounded terminals that connect to nothing else.
  • Mark Swanson, guitarist, MIMForum Staff
Jason Rodgers
Posts: 1554
Joined: Fri Jan 06, 2012 4:05 pm
Location: Portland, OR

Re: Wiring help: accidental kill-switch!

Post by Jason Rodgers »

I think "connected to nothing else" is the key to the bypass in this situation. In the push position, it's a dead end for the signal; in the pull position, it filters through the cap as the pot is turned counterclockwise.
-Ruining perfectly good wood, one day at a time.
Post Reply

Return to “Electronics”