Series-Split-Parallel Wiring Modification

I modified the wiring of my Washburn WI-64 (Idol) guitar, but the new circuit can be applied to any dual-humbucker guitar as long as the humbuckers are splittable (4 leads plus ground).

The original WI-64 wiring has Washburn's VCC (voice control contour) circuit. The VCC allows subtle blending of series and parallel sounds. However, it doesn't permit true single-coil operation and doesn't leave room for a conventional tone control. Moreover, Washburn wires the guitar with separate volume controls for each pickup, which makes quick volume adjustments difficult.

Original wiring for WI-64 guitar

I started out looking at a more complicated switching arrangement, with a conventional 3-way neck/both/bridge switch plus separate series/parallel/single-coil switching for each humbucker: 15 combinations. However, many of the settings were not very useful. The neck or bridge single-coil settings were noisy individually. The series-wired neck pickup sounded too muddy on its own, and the parallel-wired neck pickup didn't blend well with the bridge pickup. And I didn't like having to change several knobs just to switch from dual-single-coil to bridge humbucker.

15-way wiring for WI-64 guitar

The new circuit is much simpler, replacing Washburn's 3-way (neck/both/bridge) switch with a hard-to-find 4P3T rotary switch. (I found mine at www.ampwares.com, along with the chicken-head knobs.) The new switch offers: (1) neck humbucker wired in parallel, (2) neck single-coil + bridge single coil (wired in a humbucking arrangement like a Strat in positions 2 or 4), and (3) bridge wired in series. The remainder of the circuit is a conventional tone control and volume control. This reduces the number of controls from 5 to 3.

3-way wiring for WI-64 guitar

4P3T switch

I found that these 3 positions offer very different tonal colors. Parallel-wiring the neck pickup gives a crisp yet bassy sound, sort of like a vintage PAF. The single-coil position gives a clear, tele-like sound which sounds great clean. The series-wired bridge pickup is bright and midrangey and distorts nicely. I used a smaller-than usual .0068 uF tone capacitor, which gives a honky sound when turned down, a very useful addition to the tones available on the stock WI-64. (You might prefer a .022 uF cap, particularly with the low-source-impedance single-coil and parallel-neck positions.)

In the end, I added an extra rotary switch to choose the capacitor value: .0068, .022, or .055. I also added a momentary pushbutton switch to short the output, for an extreme tremolo effect. I don't plan on using it much, but it fills an unneeded hole on the original WI64. The body and the wiring cavity of the finished unit are below:

Links

Fixxxer's page on the Washburn WI-64

Guitarelectronics.com wiring diagrams