Thoughts on pickup conductor cable capacitance...

[Bowtomecha]

I was wondering for a while about this, and saw that the owner of Zexcoil had done some research on the effects of shielding and shielded cable on capacitance in electric guitars.

https://www.thegearpage.net/board/i...effects-on-pickup-resonant-frequency.1162900/

Plainly, that a guitar with shielded cavities and unshielded internal wiring has less capacitance than a shielded guitar with shielded wiring. As in the 4 conductor shielded wiring found on humbuckers. The article is a bit wordy but clear in its results. I’m wondering if anybody else has found this to be true. I’m also wondering if anybody has simply used unshielded 4 conductor wiring along with a ground wire for the baseplate, and with shielded cavities for a good result.

While I’m near the topic, I shielded my guitar fully, including the pickup cavities. I have direct mounted pickups with the screws going through the baseplate screws through the copper foil into the wood. Perhaps I should’ve trimmed the foil away from the holes more? I’ve noticed some noise since I last swapped my pickups out after the shielding and I think it’s just the house electrical environment changes but I wanted to eliminate the source being a possible ground loop between the baseplate ground to the electronics and the baseplate possibly grounding through the shield to the electronics. I didn’t think it was possible that a guitar could have two different ground potentials because the ground leaves the guitar through one jack but is it possible? I know people say to have every thing grounded to one point inside the guitar but I haven’t seen the science behind it demonstrated.

 

[freefrog]

Re: Thoughts on pickup conductor cable capacitance...

Plainly, that a guitar with shielded cavities and unshielded internal wiring has less capacitance than a shielded guitar with shielded wiring. As in the 4 conductor shielded wiring found on humbuckers. The article is a bit wordy but clear in its results. I’m wondering if anybody else has found this to be true.

Yes.
Each time you have a wire close to another wire with an insulation in between, it builds stray capacitance.

Now, IME/IMHO...
-capacitance is NOT necessarily a bad thing. In a LP, for example, the massive stray capacitance due to a fierce lenght of braided shielded wire contributes to that desirable Gibson mid voicing, especially when the two PUs are enabled. conversely, reduced capacitance can result in a very harsh tone;
-stray capacitance of pickup wires is negligible compared to the stray capacitance of our typical guitar cable. It matters to some extent because it affects the behaviour of volume controls... but the difference due to low capacitance is subtle and, once again, not always "better" sounding.

EDIT: granted, if you want a 4 conductors pickup to sound more like a 2 conductors one, separate wires will do a bit better than 4 wires in a common shield... BUT they won't cancel totally the unavoidable capacitive effect acting like a comb filter beyond the primary resonant peak with most Humbuckers.

I’m also wondering if anybody has simply used unshielded 4 conductor wiring along with a ground wire for the baseplate, and with shielded cavities for a good result.

Yes. And FWIW, that's exactly how DiMarzio designed the Brian May single coils, meant to be wired in series in order to form an humbucker : each pickup had a black wire, a white wire, and a separate ground wire connected to the U shaped BP of the coil... It worked.

Some Bill Lawrence pickups (like his "Wilde" L500) also feature(d) separate wires and don't make noisier a properly shielded guitar IME.
EDIT for a visual example of what I was taliking about: https://reverb.com/fr/item/6614082-...de-pickups-l500xl-bridge-humbucker-2017-black