February 2011 – Planet Z

Bourns PDB183-GTR01-504A2, Gibson PPAT520, AllParts EP 4286-000

February 16, 2011

Push/Pull Pots

Guitar Electronics, Potentiometers, Push/Pull 53

Let’s take a look at push/pull potentiometers. Shown here are three specimens- Bourns PDB183-GTR01-504A2, Gibson PPAT520, and AllParts EP 4286-000. These are all 500k audio taper pots with knurled split shafts. The EP4286 has a longer 3/4” shaft, while the others have the standard 3/8” or “short” shaft. This Bourns has the highest torque of the bunch– it’s the hardest to turn, while the Gibson is the easiest, and the AllParts has just a touch of mechanical graininess to the feel.

A push/pull pot is just a potentiometer sitting on top of a DPDT switch. The switch actuator is the shaft of the pot itself, which drives down right into the switch. When you pull the shaft up, you are moving the switch actuator to connect the top half of the switch, and when you push the shaft down, you are moving the switch actuator down to connect the bottom half of the switch. There’s no built-in electrical connection between the pot and the switch – if you want the switch to control the pot’s behavior, you need to connect up some wires (as in the example described at the end of this article).

February 4, 2011

Ideas for Treble Bleed Problems

Guitar Treble Bleed Capacitors, Electronics, Epiphone Riviera P93 38

Update: I describe my final mods in this post.

A while back, I described some problems with trying to use treble bleed on this guitar with three volume pots and a 3-way switch. When turning down one volume pot, that pickup retains brightness, but the other pickups get duller. In this diagram, with middle and neck pickups in a blended switch position, the middle volume is up full and the neck volume is turned down. The middle pickup high frequencies have a path to ground through the neck treble bleed cap. More

February 3, 2011

Difficult Decisions

Guitar Capacitors, Electronics 0

Nearly every day, I receive a question like “I have a Custom Slender Flatoblaster with Fleemore Dunkin pickups. What brand and values of pots and capacitors should I buy to get a killer sound for Jazz Country Electro Fusion Metal Ambient Rockabilly?”

I’ve tried to be clear in my posts and videos evaluating guitar electronics, that these things are really subjective and a matter of personal preference. I could tell you that I like CTS brand EP0086 500k audio taper pots for both volume and tone, and Orange Drop 715P .01uF tone capacitors, and these work really well for me. But, you may buy these same components and hate them. More