Jazzmaster Dial-a-Tap Wiring
Q: What is Dial-a-Tap Wiring
Dial-a-tap wiring is like a coil splitting switch (between single coil and double/humbucker) except you control a blend between the two with a potentiometer. Brilliant!
Q: Why do I want Dial-a-tap?
Well, you can focus in on a range of sounds.
Q: Is a Jazzmaster suited to Dial-a-tap modification?
Yes and no. Jazzmaster default pickups are single coil, so you can’t tap a single coil. So, you’ll need humbucking pickups like Curtis Novak JM-HC (the non-humbucker is Curtis’ single coil JM-v)
What the Jazzmaster does have going for it is the rhythm section built in to the guitar: no routing, no drilling, space and bracket for pots are already there….again: Brilliant!
Here is a video of me demonstrating the dial-a-tap wiring:
Here are the basic steps to follow:
- You can always order a pre-wired kit from Rothstein Guitars. In fact, I made my kit from a Rothstein kit that I modified. He ships his kits with EVERYTHING you need. Now, if you don’t do the Rothstein kit, or want to mod it, here are some notes/instructions:
- You’ll need to source some double coil pickups that have a coil tap. The coil tap means that there is an electrical connection between the two coils of the humbucker. Some humbuckers only have 2 wires, some have 3 wires, and some have 4 wires. The 3 wire or 4 wire humbuckers have a tap.
- Now, the Curtis Novak JM-HCs that I used were advertised as “Can add a tap”. When I got them, they had two wires, but a single center solder point between them, but no wire attached. I added the red wire shown here:
- An electrical meter is your friend here. I set my meter to Ohms and tested red wire to white, about 5600 ohms, and red wire to black, about 5600 ohms, and white to black about 11000 ohms. Bingo! the red is a working center tap.
- There is a schematic which shows the wiring at the bottom of this post.
- I tried this wiring first with 500k linear mini pots in the Jazzmaster rhythm section and I got the full range of single-to-double coil between 0 and 1 on the volume knobs. Remember what is happening electrically here…the rhythm section mini-pots, as you rotate, send signal to ground–basically grounding out one of the coils (because you are grounding from the center tap) leaving one of the coils to send signal out the jack. Because it takes very little signal to ground out a humbucker, I found that 100k Audio taper pots worked better than 500k and gave me nearly a full range of variability between single and double coil.
- While you’ve got your Jazzmaster apart, why not wrap the entire wiring cavity in copper foil?