Researching dummy coils. I have bunch of ceramic single coils I can test with, or wind some up. Looks like their are different ways to wire it. Most guitars are already in parallel in phase. I’ll test serial in phase rwrp. See how it affects tone. Not sure how I would test resonant peak but I’d have to probably rewind the p90s I have. Which I wanted to do anyways. I can test with a cable jack and plug and wire it in series or parallel.
Also can use a noise suppressor, but I’ve noticed the hum is still there when letting notes sustain out. As the volume drops the hum becomes more apparent.
Also I read somewhere that the coil has to be on same plane. Definitely will test that.
It will definitely raise the DC values. Which may be a good thing with the passive clipping diodes mod I may add to my guitar builds.
Other options, convert the single coils to noiseless. Either by stacking the coils or cutting them in half.
Adding a dummy coil to another pickup is usually done to make the working single coil pickup humbucking or quieter in the instrument. Some companies use the pickup directly under the strings without using pole pieces and others rout a cavity away from the proximity of the strings.
Using a dummy coil the DC resistance will change along with the tone and frequency response of the existing pickup. The inductance will change when testing a pickup. The dummy coil can either be used in series in phase or series out of phase, or parallel in phase or out of phase. When adding coils remember it can change the tone or phasing of your instrument when used in combination with other pickups.
https://www.1728.org/guitar1b.htm
Also can run the dummy coil in parallel. Supposedly giving more of brighter tone. The dc resistance isn’t doubled.