1 Humbucker, 1 Volume, 5-way, and interesting options

[Jason Rodgers]

I found a very interesting way to wire a 2 pickup Telecaster style guitar on this link: http://music-electronics-forum.com/t42809/ see post #8.

When two pickups are selected in either series or parallel (using a 4-way Telecaster selector switch) and put out of phase, an interesting notch shift occurs with only about one tenth of a turn of either stacked concentric volume 500K pot that individually controls the volume of each pickup. The pots are wired with the pickup hot output going to the pot center lug and the output taken from the outer lug for ground and the other outer lug to go to the selector switch. Use a tone pot with a push-pull DPDT to flip the phase of the neck pickup. Those choosing to not use individual volume pots attain a fixed out of phase effect by adjusting the pickup height but the variable effect of using stacked concentric volume pots adds more variety.

Joseph J. Rogowski

Is this similar in effect to what rjb referenced in post #2?

[Jason Rodgers]

I might be interesting to put one end of the cap to the series link and then connect the other end to either ground or output. I need to experiment more with the tone control but usually pickup switching uses all the switching options (and my brains). Have you checked out the Fender TBX control?

The Fender TBX Tone Control, Part 1

So, you're saying hook one leg of the cap to the series connection, ground the other leg, and find out what kind of filtering results? I'll add that to the list of things to test (unless someone comes along who actually knows what all these hypothetical scenarios would do).

And no, if I've heard of or read about the TBX, I've forgotten. Hmm, a treble/bass tone pot... this might change my ideas about the volume only setup.

[bbsailor]

Is this similar in effect to what rjb referenced in post #2?

Yes, but with the volume pots wired for independent control of each pickup to control the notch effect when out of phase in either series or parallel.

Joseph J. Rogowski

[Richard]

I don't know what's going on but from center counterclockwise it's a regular tone control, from center clockwise it seems to just take the load off of the pickup and it gets brighter and louder. It seem like it would be a pretty heavy load in the center with the 82K resistor.

[Jason Rodgers]

Yes, but with the volume pots wired for independent control of each pickup to control the notch effect when out of phase in either series or parallel.

Joseph J. Rogowski

Gotcha.

Say, Joseph, you have a lot of theoretical and practical knowledge when it comes to "wrapping your head around" this stuff. Do you know what would happen if a capacitor was inserted in various locations around the pickup's 4 hookup wires as we've been discussing here? There are 5 scenarios, I think:
1. Cap in series on the hot end (which is the high pass, like a treble bleed).
2. Cap in series between the coils (bridging the series connection).
3. Cap in series on the ground end.
4. Cap in parallel on the hot end (which is the low pass, like a typical tone pot).
5. Cap in parallel between the coils (one leg in the series connection, one leg to ground).

[bbsailor]

Gotcha.

Say, Joseph, you have a lot of theoretical and practical knowledge when it comes to "wrapping your head around" this stuff. Do you know what would happen if a capacitor was inserted in various locations around the pickup's 4 hookup wires as we've been discussing here? There are 5 scenarios, I think:
1. Cap in series on the hot end (which is the high pass, like a treble bleed).
2. Cap in series between the coils (bridging the series connection).
3. Cap in series on the ground end.
4. Cap in parallel on the hot end (which is the low pass, like a typical tone pot).
5. Cap in parallel between the coils (one leg in the series connection, one leg to ground).

Jason,

Any time you put a capacitor in series with a source ac voltage you create a high pass filter since the capacitors reactance goes down with higher frequencies. Try this: put various values of capacitors (.001, .01, .1 and 1 uf) in series with your pickup and then simply put a SPST switch across it and listen to the sound with the switch open and the capacitor in series then throw the switch to short out the capacitor actually removes it from the circuit. Do this in various places of two coils, in the middle between two coils, then just above the ground connection, then just above the hot connection and listen for tonal changes with the switch open and closed. Capacitors in parallel with an ac source signal, makes a high cut, like a typical tone control. Tinkering is a good form of learning.

Joseph J. Rogowski

[Dave H]

1. Cap in series on the hot end (which is the high pass, like a treble bleed).
2. Cap in series between the coils (bridging the series connection).
3. Cap in series on the ground end.

If what you have is coil, coil, cap in series then those three options above are the same, the order shouldn't matter (as rjb said in post #10)

[Jason Rodgers]

Stopped by Fry's today and grabbed a couple things to get my test rig running. Might be a bit before I can report back, but I appreciate the resources and knowledge that folks have contributed thus far. This went in a totally different direction than I thought when first considering a 5-way on one pickup: from basic coil pairings, cutting, and phase switching to filtering with caps. I have plenty of options, now. Thanks!

[Jason Rodgers]

I have a late start at work today, so I ran out to the shop to do a little testing. I rewound a cheap, dead pickup (brass baseplate, ceramic magnet, both coils with slugs) with 5000 turns of 42awg on each coil to get 7.36k. I played it straight, recorded, and then put a .022uF cap in different places and recorded the results.

- In series (and yes, I tried it in all three places - ground, series connection, hot - to hear for myself that, yes, it's all the same).
- In parallel on the hot, to simulate a tone pot rolled off.
- In parallel at the series connection.

The first two scenarios gave me what I'd expect: cap in series gave me the high pass, cap in parallel gave me the low pass. What was really interesting, though, was the cap in parallel on the series connection that Richard suggested (one leg of the cap on the series connection, the other to ground). This was a sound somewhere in between, with slightly scooped mids. This must be that "half" sound that rjb described earlier, but what you get with it in series in phase. I guess one coil would read the cap as parallel, and the other coil would read it as series. Pretty cool!

I'm going to have to run the whole experiment again (minus the redundant series wiring) with different cap values. I have .001uF, .047uF, and .1uF. I'd like to find a value for series that gives me slightly more bass cut, and a value for parallel that gives me slightly less treble cut. I can't remember which way you go in value to get which result. The parallel on the series value is ok, but I might find something I like better.

So right now, if I went with this all-series with various filtering caps wiring scenario, I could have 4 positions on my 5-way: unfettered, treble cut, bass cut, and the "half" cut. Maybe I need to test out some parallel and out of phase options, too.

[Richard]

Did you try the cap from the series connection to the output? Now I want to try this but I have too many wires in my guitar already. I'm also wondering what this would do to a stacked humbucker.

[Jason Rodgers]

Did you try the cap from the series connection to the output? Now I want to try this but I have too many wires in my guitar already. I'm also wondering what this would do to a stacked humbucker.

No, I didn't do that one. So, you're saying instead of running a leg from the cap to ground, run it to hot? Wouldn't that effectively put the cap back in series?

I don't know about a stacked humbucker, but I want to try this with two full humbuckers. With that "half" wiring, you could low pass the bridge and high pass the neck, or viceversa. Any way you cut it, this is a third option to filter with a cap.

[rjb]

What was really interesting, though, was the cap in parallel on the series connection that Richard suggested (one leg of the cap on the series connection, the other to ground). This was a sound somewhere in between, with slightly scooped mids. This must be that "half" sound that rjb described earlier, but what you get with it in series in phase. I guess one coil would read the cap as parallel, and the other coil would read it as series. Pretty cool!

That is pretty cool.

Not the same as "Half Out of Phase" - that's more of a comb-filter kinda bag.

[Jason Rodgers]

This weekend I'm going to run it all again with different caps. Correct me if I'm wrong, but I seem to remember reading that the smaller the cap value, the higher the pass frequency point. Is that right? So, in the series scenario, a .001uF cap would cut more low end than .022uF; in parallel, it would cut less high end. Another way to say it would be more bright on the one hand and less muted on the other. Or do I have this backwards, and a larger cap value would have this effect?

[Richard]

The smaller the cap, the higher the frequency. I want to try this on the taps for my stacked humbuckers.

[Jason Rodgers]

I was out in the shop again today, swapping out caps and listening to results. Here are a couple observations I made regarding the parallel cap on the series connection:
- I confirmed that, yes, one coil sees the cap in series and the other in parallel. Simply by tapping on the slugs with a screwdriver, I could hear that the coil that connects its start to hot is getting the series high pass, and the other coil that has its start connected to ground is getting the parallel low pass. In my test rig, this was the neck side and bridge side coils, respectively. Since both are slug core coils, it probably wouldn't sound much different if that was swapped, but I bet there'd be a difference between slug and screw core coils, or if one were a blade.

- I tested. 001, .022, and. 047 uF caps. The. 001 and. 047 caps shifted frequency responses around, but in subtle ways, like slight adjustments at the amp. It was the. 022 cap that gave a very obvious midrange scoop. This must be affecting a specific frequency band as determined by the pickup's frequency profile. In other words, that. 022 cap is hitting that perfect notch for that scoopy sound, but might not have that effect on a different pickup that is wound hotter. It might take some more experimentation to find out what caps work best with which pickup type for this sort of effect.