3 volume wiring with phasing

[ajent__smith]

heres my idea:

(i think) this mod can be done with 3 DPDT push-pull pots and should give you all the parallel pickup combinations as well as individual volume controls. I realize that when out of phase the sound will get quieter when i turn one of the pickups up.

I guess i have 2 questions:
1. will it work.
2. if the middle pickup is RWRP, then when I have one of the other pickups turned all the way down, and the other one all the way up, is it humbucking?

for example, if the pickups are all in phase, i have the neck volume at 10, the mid volume at 10, and the bridge at 0, is it humbucking?

thanks in advance,
-Ajent

[Runewalker]

I sorta like the idea of a vol control for each pup, but others have shot that down as (excuse the lay explanation) too much additive resistence in the circuit stream.

I have an experimental set up worked out with JH that allows kicking in all three pups, or two or whatever combo you like. When you test the output resistence, all pots wide open, you see the multimeter go from say 6K ohms with one pup, to 3K ohms with two, to 1.5K with three. In this set up I have a blend control on the neck. So with all three pups in, I can roll the neck full on and the other off. Now, compare that sound (all three pups with only the neck rolled on) with neck only, and the other pups off, and the sound is significantly different.

So in your example you will not be able to avoid the systems effect of adding pups in parallel. The vol controls will not be the same as say half an EQ, where you roll off output of the independent pups or roll up to full on (the half way point on an EQ), because of the additive or subtractive electronics involved with combining pups in either parallel or Series.

I like your idea, but passive systems don't quite cooperate. It would be nice to be able to treat the vols as mixer sliders bringing up or down the output of a different geographic pup to render tonal variations. I have been instructed this is unrealistic.


But I will let more knowledgible folks address the actual electronic issues.

[JohnH]

I think it would work, but with all those pots across the output you could lose some treble. So it would need higher value pots that a normal Strat. At least a 500k, or maybe 1M. The phasing would work, and you'd get the same hum-cancelling options as on a circuit with switches, being N+M and M+B. Also B+N out of phase will hum cancell. An interesting effect with the out of phase is that youll be able to tune the pickups to totally zero out the fundamental frequency, or let some of it come through.

This circuit is not a bad idea if you are happy with parallel sounds, and dont mind the time taken to adjust each pot, rather than a quick switch change to do a solo.

Using high value pots can make it vulnerable to cable capacitance losses and some interfence. If you find this, a one transistor on-board buffer amp could fix it, and give you a boost for overdrive. No need to do this to start with, but its an option if you need it.

ps. Some of the problems that RW is refering to are on our Tonemonster thread, where we are doing series and parallel circuits. RW has done an excellent trial build of our 3 pup circuit with all series and parallel options. It is for this that I have had trouble working out independent volume controls, or blend controls, which work in a matched way between series and parallel settings. This is because the characteristics of a volume control for a series circuit are very different to these parallel ones. We are working towards a switched arrangemnt where a rotary dials in carefully chosen resistors to give consistent results across settings.

.

[Runewalker]

As usual JH, you are so much the man.


JH is right about a number of things, and this issue of what looks good on paper in terms of total output control, is somewhat of a different animal in a live play situation. I can dial up a panopoly of sound unheard from a strat before, because of all the switching and volume attenuation, but getting to them fast is another issue.

The other thing is there is a significant aural and output difference between 3 pups engaged in parallel and 1 put or even two. If you plan to park on three then compete soundshaping with boxes, modelers, amps or what ever, then the 3 one all the time and equed with volume would probably work, but critical and importantly, hearable differences occur in out put and tonal characteristice when adding or taking pups out of the stream.

It completely depends on your sound and realtime objectives.

One other thing is the character of your pups. I just switched out a set of ceramiics that were really pretty serviceable to some alnicos that are full range and a slight bit overwound. My ears are now bleeding in terms of treble. So with these type pups there is plenty of treble overhead to attenuate with a little increased system resistence.

RW