Pickups - a technical question

[Fruktfat]

As we all know the in-between posistions on a strat's pickup-switch gives a very clean bell-like tone. The Les Paul is a different guitar, but you can hear it there as well - when both pickups are on and equal in volume, the sound has a clearer quality with more highs. Barring any custom wiring both of these positions connect the pickups in parallel(?). My question is this: Is the brighter tone related to the drop in impedance you get when connecting two coils - or lightbulbs for that matter - in parallel? If so, I thought this primarily had an effect on DC resistance?

 

Any info would be greatly appreciated.

 

Fruktfat

[Major Tom]

That's a good question. I have heard in the past that it is due to the fact that the two pickups are physically out of phase - not 180 degrees like out o'phase pickups, but since they are picking up different sections of the strings vibes, there is some phase cancellation going on there. I would suspect that the coils in parallel having a lower impedance would also be part of it, that's not just a DC thing. Bill Lawrence used to sell an inductor to use in custom guitar wiring/switching schemes; as I remember the purpose was to get a different, more single coil tonality by switching this into the circuit in parallel with the pickup(s). Since inductance cuts high freqs,lowering the total inductance of the circuit by half with coils in parallel would decrease the attenuation of the high freq content.

[Blue Strat]

Pickups (and any other AC circuit) have three components: resistance, inductance, and capacitance. The resistance is halfed in parallel, capacitance is doubled in parallel, and the inductance is halfed. This is of course only if the pickups are exactly the same, which we know isn't the case.

 

I don't hear what you're calling "a clearer quality with more highs" on the Les Paul's middle setting. I hear a muddier tone than the bridge pickup alone, and a clearer tone than the neck pickup alone. A Strat's neck and middle pickup are at positions on the guitar's body where the phase of the sinewave produced by the string cancel each other out somewhat. This is what produces the unique tones at positions 2 & 4 on the Strat. A three pickup Les Paul displays that characteristic, but I haven't heard it on a two pickup Les Paul or Telecaster.