Help, ideas: SSS kit guitar

[stevewf]

Hi Nutz2's. I bought one of Stewmac's "Offset Trem" kit guitars (stock photos on Stewmac site here). I intend to modify it while building it; like stainless steel frets, better trem, different pickups, different wiring and controls.

The biggest change I'm planning is to use three single coil pickups, kinda like a Strat, including a RWRP middle coil. Unlike a Strat, the middle coil would be moved right next to the bridge coil. So the pickups would look like a Humbucker and a Single coil. I'd been cooking the idea for a while, and then was emboldened by Squier's Contemporary Stratocaster Special. I was pleased to see that in addition to scooting the middle coil, they'd changed the function of the blade switch - there's a serial combo in there, and an all-coils one (not documented, but I bet the all-coils is (BxM)+N).

The controls I've settled on: a 5-way pickup selector, a master Vol, a master Tone and a Phase switch push-pull in one of the pots.
I'd like the switches to do this:
5-way:

Pos#	Coils
5	Neck
4	Bridge (single) + Neck
3	Bridge (single) x Neck
2	Bridge (single)
1	Bridge (series HB)

Phase switch affects positions 3 & 4:

Down	In phase
Up	Out of Phase

Here's a schematic of a solution that I think covers the above (Postimages)

SPOILER: Click to show

There's an unused pole on the Superswitch.
I couldn't figure out a way to use 2-gang pots to offer separate Vol/Tone circuits for Position#3 (serial) without needing two poles of the 5-way. I'm choosing 500K needles instead of 250K mud.
There's a way to get either of the Bridge coils alone, using Position#2: Phase Dn=Inner, Phase Up=Outer.
I could invert the Phase switch (i.e. make it Up=In Phase) by swapping the two pairs of throws on s2. But I favored Down=In Phase.
To get In-phase hum cancelling, it's easier to find RWRP middle coils (harder to find one of the outer coils RWRP).
Coupled with an RWRP middle coil, this means that "normal" (In Phase) uses the inner coil in Positions#2, 3 & 4 in my schematic. (Again, to get the outer Bridge coil alone, it's Position#2/Up)
I wanted Position#1 to be Bridge Series. Fiddliness to get the Bridge Outer coil alone is a consequence.
I considered a series fader. There'd be a bit more body routing to add a 3rd control knob, which would be a but tightly clustered.
I considered moving the jack to the edge, in order to free up space in the control cavity. Sounds like a lot of Forstner. I have a cordless hand drill. Gulp.

These mods will require a new pickguard (getting rid of the 3-way toggle, instead using a 5-way blade near the lower horn) and some body routing (for the blade switch and its wire channel). But like I said, I've settled on these controls, with maybe-maybe-maybe also using the cavity where the 3-way used to live (upper horn).

Here's what I'm asking for:

• A vetting of the schematic, and proposals for improvement
  
• Any warnings about the proposed physical pickup layout. Two single coils next to each other; is it a bad idea?
• Thoughts on choice of pots (250K or 500K?).
• Ideas for using the existing rout where the 3-way toggle once lived.
• General sanity checks welcome. Anything look terribly wrong?

[newey]

Your schematic looks fine to me, but let's get another set of eyes on it. I've been looking at a monitor screen for far too long today . . .

Oct 4, 2023 19:45:22 GMT -5 stevewf said:

I considered moving the jack to the edge, in order to free up space in the control cavity. Sounds like a lot of Forstner. I have a cordless hand drill. Gulp

Well, since it's a $200 kit guitar, I guess you can chop away to your heart's content if you want to. But the risk/reward ratio for this mod seems slim.

Oct 4, 2023 19:45:22 GMT -5 stevewf said:

To get In-phase hum cancelling, it's easier to find RWRP middle coils (harder to find one of the outer coils RWRP).

Much is made of differences between neck, middle and bridge pickups these days; they sell supposedly "matched sets" where, typically, the bridge pickup is wound a bit hotter. But it wasn't always that way. On the vintage Strats, all the pickups were the same, and there was no RWRP middle (and there wasn't any reason for a RWRP middle, because the 3-way switch allowed for only one of the pickups at a time).

It is written exactly nowhere that one must use a particular pickup in a particular position. Put the RWRP coil whereever you want it for the hum-cancelling you want. If you're really terribly concerned that there will be a mismatch in relative outputs, look for a different, slightly "hotter" RWRP coil, that would more closely match the DC resistance you'd want at the bridge (or neck, whatever).

My 4-single coil Strat, the "4Caster" has 2 RWRP coils, one is at the bridge position and the other is the second middle pickup, the one closer to the neck. I paid no attention to neck coils vs. middle coils, etc. Sounds just fine, don't really notice any mismatches.

General sanity checks welcome

Sanity checks? Are you crazy? If we did those around here, we wouldn't have a forum . . .

[stevewf]

Oops, I already found a mistake in the schematic. I've edited the OP with what I hope is a correction.
Namely, with s1a, I had throws 1&3 connected, but it should have been throws 2&3. Sloppy.
The bogus version is still at postimages.

[newey]

You know, I looked at that switch several times and didn't see that, so good that you spotted it.

[stevewf]

Thanks for looking the diagram over, newey, and also for the help with RWRP and pickup locations.

Now I'm curious about the 4Caster. I searched the forum for it and found a couple photos, and I know it has binary tree switching using alternate pairs of coils... I wonder how it sounds! Do any of the coil combos strike you as unusual sounding?

[newey]

Oct 5, 2023 9:43:08 GMT -5 stevewf said:

Do any of the coil combos strike you as unusual sounding?

It sounds different than a Strat, primarily (I think) because of the nodes along the string where the 2 middle pickups sit versus where the single middle pickup on a Strat sits. The two neck-most coils in series with the bridge pup added in parallel is one of the sounds I like on it, pretty much a HS sound if the HB is at the neck position. Also, the 2 middle pickups are sort-of progressively slanted to match up with the slanted bridge, so that probably had some sonic effect as well.

The way the switching is set up, there binary tree switches for each of the 2 pairs of pickups. If we number the pickups from neck to bridge as 1-2-3-4, two switches control 1 and 3, the second pair of switches controls 2 and 4. So the "Binary tree" switching can put each pair of coils in series or parallel, or either coil individually. Then the 2 pairs can be joined together, or not, by a fifth toggle switch. so, it doesn't do all possible permutations of 4 coils, as the two pairs of pickups can't be put in series with each other.

It does have several interesting sounds, but I don't play the guitar very much as it was a very cheap, very used Strat copy which plays OK but not great. The neck isn't my favorite profile. It was always more of a wiring exercise.

[Yogi B]

Oct 4, 2023 19:45:22 GMT -5 stevewf said:

A vetting of the schematic, and proposals for improvement

At the moment the bridge is left unconnected in position 4 leaving just the neck pickup (as in pos 5) — looks like you'll need that remaining super switch pole.

Any warnings about the proposed physical pickup layout. Two single coils next to each other; is it a bad idea?

Assuming they have the typical asymmetrical flatwork/bobbin shape, getting the two as close as possible will require a 180° rotation of the middle (bridge inner) coil — thus reversing its magnet stagger (if applicable).

Thoughts on choice of pots (250K or 500K?).

As before, my default is 250k. For tone pots, I find 250k gives a more spread out sweep from bright to dark over the full rotation — for my taste, 500k bunches up a little too much change at the lower end. For volumes, once you start to turn it down, a 250k is actually a little brighter compared to 500k — a 250k pot adds less resistance in series with the signal, lessening the losses from cable capacitance (I go into more detail about this here). When set at maximum, a 250k volume pot plus a no-load 250k tone pot equates to two 500k pots.

Ideas for using the existing rout where the 3-way toggle once lived.

You did mention concentric pots for separate volume & tone controls in the series position, and whilst I agree it'd be a stretch to get that working in only that position, it should be fairly simple to add separate bridge/neck volumes/tones that work across all positions. If doing that, I'd keep the standard control positions as single gang controls for the bridge pickup(s) and use the 3-way toggle rout to house the concentric volume/tone control for the neck pickup.

Another idea, this time in keeping with your proposed global controls, would be to use the space for toggle(s) to bypass the volume and/or tone.

I considered moving the jack to the edge, in order to free up space in the control cavity. Sounds like a lot of Forstner. I have a cordless hand drill. Gulp.

Since it sounds you're comfortable doing routing, you could rout a cavity for strat jack plate on the front ... or the back:

[stevewf]

Oct 16, 2023 9:58:48 GMT -5 Yogi B said:

At the moment the bridge is left unconnected in position 4 leaving just the neck pickup (as in pos 5) — looks like you'll need that remaining super switch pole.

Oppsie-doopsie! Thanks so much for coming around to have a look, Yogi B! I guess I was suffering from "schemato-fatigue" when I made that mistake. You've reduced my inhalation of solder flux vapor!

Any warnings about the proposed physical pickup layout. Two single coils next to each other; is it a bad idea?

Assuming they have the typical asymmetrical flatwork/bobbin shape, getting the two as close as possible will require a 180° rotation of the middle (bridge inner) coil — thus reversing its magnet stagger (if applicable).

I'd forgotten about magnet stagger. Lemme see what flat-magnet coils I've got... or maybe the two coils will be separated by a small gap, which would look weird and unusual (perhaps interestingly so). I'm guessing the gap would't cause a very different sound with this particular scheme (though flat vs stagger magnets might).

Thoughts on choice of pots (250K or 500K?).

As before, my default is 250k. For tone pots, I find 250k gives a more spread out sweep from bright to dark over the full rotation — for my taste, 500k bunches up a little too much change at the lower end. For volumes, once you start to turn it down, a 250k is actually a little brighter compared to 500k — a 250k pot adds less resistance in series with the signal, lessening the losses from cable capacitance (I go into more detail about this here). When set at maximum, a 250k volume pot plus a no-load 250k tone pot equates to two 500k pots.

Certainly merits some link-clicking when I have time.

Ideas for using the existing rout where the 3-way toggle once lived.

You did mention concentric pots for separate volume & tone controls in the series position, and whilst I agree it'd be a stretch to get that working in only that position, it should be fairly simple to add separate bridge/neck volumes/tones that work across all positions. If doing that, I'd keep the standard control positions as single gang controls for the bridge pickup(s) and use the 3-way toggle rout to house the concentric volume/tone control for the neck pickup.

Another idea, this time in keeping with your proposed global controls, would be to use the space for toggle(s) to bypass the volume and/or tone.

Here I actually meant dual-gang (shared shaft) pots rather than concentric (separate shaft) ones. For the std control locations, I gotta leave room for the trem arm to swing over the controls without knocking them, and concentric knobs tend to be taller. The location of the old toggle rout, of course, doesn't affect the trem arm swing. There remain lots of options... and I'm gonna hafta choose at some point! 
 <--me, choosing

I considered moving the jack to the edge, in order to free up space in the control cavity. Sounds like a lot of Forstner. I have a cordless hand drill. Gulp.

Since it sounds you're comfortable doing routing, you could rout a cavity for strat jack plate on the front ... or the back:

Wow, a rear jack plate hadn't occurred to me. Gonna hafta seriously mull that one. It opens up even more options for the front controls. And yes, to me, routing the back of the solid guitar body (which is a broad, flat surface) seems easier than boring into the narrow edge. Never done either, though!

Thanks again, yogib, for the ideas etc!

[newey]

Didn't ocvcur to me either, but I can see the advantage. With the side jack, like on my Teles, if I'm standing with the strap holding the guitar, I have to insert the plug by feel, can't flip the guitar upwards enough to see the side jack without taking the strap off my shoulder. With the jack in the back, could just flip the guitar forward to see the jack.

[stevewf]

So here's a new version of the schematic, which I hope fixes it up:




And in hopeful anticipation that I've got it right, here's a wiring diagram based on that:


Barring any helpful warnings from the Nuts, now I've got to rout the cavity for the blade switch...