Needs phase swapping in position #3

[stevewf]

Hi y'all. OK, so I've got this guitar wired and working, but I haven't figure out how to get the phase swap to include position #3.

First, pictures always seem to be good motivators, so here's the guitar, working, as it is now:


It's clearly Strat-based, including a 3-pickup arrangement, a 5-way selector and three knobs... and with some departures from the standard Strat.

What I want with this guitar is:

• Position #3 of the selector gives Neck and Bridge pickups (not Middle) [achieved]
• All pickup pairings must be hum-canceling [achieved]
• Serial/parallel switching (when paired) [achieved]
  
• Fading of one pickup (when paired) [achieved]
• Phase swapping (when paired) [not fully achieved]
• Serial cap. filtering of one pickup -- the same one that's being faded -- when the pair is in parallel and out of phase [achieved]

Here's the rub, and where I'd like help
The [not fully achieved] part is about that position #3; the phase switch has no effect there, though I want it to. I haven't figured out how, even with some special components in the guitar.

Anyone see a way?

Puzzle solvers' playground and constraints:
Here's what's in there now, getting me this far:

• A pair of hum-canceling P-90s in the Neck and Bridge positions (i.e. hum-canceling when in phase). Each coil gives medium (or medium-high) output
• A twin high-output rail pickup in the Middle position (also hum-canceling pair of coils). Each coil gives medium output
• A 4P2T mini-toggle
• A 6P5T selector switch (postimg.cc) (extra pair of poles over the usual SuperSwitch)
• A 4P2T push-pull switch (postimg.cc) under one of the pots (extra pair of poles)

Here's a schematic and wiring diagram of how it got this far, in case they help (click them for bigger versions hosted at postimg.cc):


note: text in the schematic is now updated, following sumgai's suggestions, below

There are two switches that each have an extra, unused pole :  the 5-way blade switch and the push-pull switch (currently serving as the pickup selector and the phase switch, respectively).

You'll have noticed that I went out of my way to filter a given coil when the chosen arrangement is Parallel and Out of Phase. It's filtered by applying a capacitor in series with the coil. I feel pretty strongly about keeping that feature, while also not applying such a filter when in serial mode. POoP sounds like whereas PFOoP is more useable, and SOoP is good on its own. Unfortunately, my filtering wishes demanded extra poles on some controls.

Aside from that, I hope that any new design doesn't require further modification of factory switches or of the guitar cavity (and pickguard, maybe); I'm kinda burnt out on modding those after getting this far! Here's a gallery of photos of this guitar so far (postimg.cc) that shows some of them.

As it stands, I like the guitar, so I'll keep it like this if no answers come. But if there's a solution for truly global phase swapping (SOoP and PFOoP), then I'll open 'er up again -- and post a final writeup of this project. Been a couple years in the making so far.

Thanks in advance for any help!

[Yogi B]

Jun 14, 2023 18:12:16 GMT -5 stevewf said:

• All pickup pairings must be hum-canceling [achieved]
• Phase swapping (when paired) [not fully achieved]

The first thing to note is that the two quoted points are fundamentally mutually exclusive for position #3 — i.e. if modified to give B & N OoP it won't be hum-cancelling. I don't doubt you already know that, but I'm just pointing out you can't have EVERYTHING.

Aside from that, I hope that any new design doesn't require further modification of factory switches or of the guitar cavity (and pickguard, maybe)

So adding a duplicate of the PFOoP cap is fine?

That is, I do think I see a way to do it, but will require a reasonable amount of circuit shuffling and the aforementioned extra cap.

[helpingfriendly]

Jun 14, 2023 18:12:16 GMT -5 stevewf said:

Hi y'all. OK, so I've got this guitar wired and working, but I haven't figure out how to get the phase swap to include position #3.

First, pictures always seem to be good motivators, so here's the guitar, working, as it is now:


It's clearly Strat-based, including a 3-pickup arrangement, a 5-way selector and three knobs... and with some departures from the standard Strat.

What I want with this guitar is:

• Position #3 of the selector gives Neck and Bridge pickups (not Middle) [achieved]
• All pickup pairings must be hum-canceling [achieved]
• Serial/parallel switching (when paired) [achieved]
  
• Fading of one pickup (when paired) [achieved]
• Phase swapping (when paired) [not fully achieved]
• Serial cap. filtering of one pickup -- the same one that's being faded -- when the pair is in parallel and out of phase [achieved]

Here's the rub, and where I'd like help
The [not fully achieved] part is about that position #3; the phase switch has no effect there, though I want it to. I haven't figured out how, even with some special components in the guitar.

Anyone see a way?

Puzzle solvers' playground and constraints:
Here's what's in there now, getting me this far:

• A pair of hum-canceling P-90s in the Neck and Bridge positions (i.e. hum-canceling when in phase). Each coil gives medium (or medium-high) output
• A twin high-output rail pickup in the Middle position (also hum-canceling pair of coils). Each coil gives medium output
• A 4P2T mini-toggle
• A 6P5T selector switch (postimg.cc) (extra pair of poles over the usual SuperSwitch)
• A 4P2T push-pull switch (postimg.cc) under one of the pots (extra pair of poles)

Here's a schematic and wiring diagram of how it got this far, in case they help (click them for bigger versions hosted at postimg.cc):


There are two switches that each have an extra, unused pole :  the 5-way blade switch and the push-pull switch (currently serving as the pickup selector and the phase switch, respectively).

You'll have noticed that I went out of my way to filter a given coil when the chosen arrangement is Parallel and Out of Phase. It's filtered by applying a capacitor in series with the coil. I feel pretty strongly about keeping that feature, while also not applying such a filter when in serial mode. POoP sounds like whereas PFOoP is more useable, and SOoP is good on its own. Unfortunately, my filtering wishes demanded extra poles on some controls.

Aside from that, I hope that any new design doesn't require further modification of factory switches or of the guitar cavity (and pickguard, maybe); I'm kinda burnt out on modding those after getting this far! Here's a gallery of photos of this guitar so far (postimg.cc) that shows some of them.

As it stands, I like the guitar, so I'll keep it like this if no answers come. But if there's a solution for truly global phase swapping (SOoP and PFOoP), then I'll open 'er up again -- and post a final writeup of this project. Been a couple years in the making so far.

Thanks in advance for any help!

Dude I really admire your out of the box thinking and setup. Sounds like a killer pleather of tonal options. I too am currently tring to figure out how to get more than the standard pickup selection of a strat.  One of the things is Middle and bridge in series which is also from Brian May's guitar ( my problem is i have a dummy coil installed)  So I've been seeing his name alot lately in my research lol. Really cool stuff man good luck with it! 

[stevewf]

Jun 14, 2023 20:16:28 GMT -5 Yogi B said:

The first thing to note is that the two quoted points are fundamentally mutually exclusive for position #3 — i.e. if modified to give B & N OoP it won't be hum-cancelling. I don't doubt you already know that, but I'm just pointing out you can't have EVERYTHING.

Oops, yes, that's correct, it is a hum-gatherer, and I did know that, but forgot to mention. Still, in this one case, I thought the desire for the tone beats my hum-o-phobia.

So adding a duplicate of the PFOoP cap is fine?

That is, I do think I see a way to do it, but will require a reasonable amount of circuit shuffling and the aforementioned extra cap.

Yesyesyes!!! Extra cap would not be a problem, and neither is ripping all the current wiring out and starting again. Thanks for looking into it

[stevewf]

Jun 14, 2023 22:10:41 GMT -5 helpingfriendly said:

One of the things is Middle and bridge in series which is also from Brian May's guitar ( my problem is i have a dummy coil installed)  So I've been seeing his name alot lately in my research lol. Really cool stuff man good luck with it! 

Have you seen JohnH's "Strat SP"? It offers a global Series/Parallel switch and a global Phase switch for SSS and SSH Strats. The dummy coil might make it a little more complicated, though. Good luck with your quiet Strat, too!

[sumgai]

Jun 14, 2023 18:12:16 GMT -5 stevewf said:

The [not fully achieved] part is about that position #3; the phase switch has no effect there, though I want it to. I haven't figured out how, even with some special components in the guitar.

I dunno, but the drawing(s) I'm looking at show S3 (the alleged phase switch) connected to the Middle pup. Kinda hard to figger out how that's gonna flip the phase of either the Neck or the Bridge pickup, when in Position 3.....

Your Truth Table says that in. Pos' 2 and 4, you can use select either M(n) or M(s), and that seems to be the job that S3 is accomplishing, at the moment.

While I can't read your mind, I'm able to offer some suggestions that might be useful, or maybe not....


1) Leave off of selecting which coil of the Mid to engage, and move S3 to act as the desired phase switch on either of the other two pups.  This leaves the Humbucker intact in the circuit, and hopefully that will be something you can live with.

2) If you must have a single coil operation in the Mid position, then replace that pickup as appropriate, and carry as in Choice 1.

3) Procure yet another switch, and place it on either the Neck or Bridge pup - leave everything else intact. (This can be a dead-stock push-pull on either of the remaining controls..)

4) Do away with the small filter cap on S3c, and use both that and (the currently unused) S3d to effect the phase reversal. At that point, your Truth Table becomes... truthful. From your point of view, this might make the most sense.


EDIT: Oh hey.... Did you mean that Pos 3 should always be out of phase, and that a switch should not be necessary? Then simply swap one of the pickups leads, permanently. But in doing so,  I have a feeling that this won't meet your expectations when in Pos. 2 (or 4) - that combo will also be out of phase.  I ask this because your diagrams both denote in text, but don't actually show, S3 as selecting phase.  In fact, I almost forgot to say something, but a studious look at the Truth Table reveals nothing about Pos 3 being out of phase, either by permanence or by selection.   I'm sure you'll agree that that's the kind of detail that would be helpful to others, when reviewing your diagram(s).

(Addtional reasoning: sometimes a casual viewer will "borrow" a diagram, and not bother to copy all of the surrounding explanatory text.  It's nice to think that even if they never come back, at least they got something out of The NutzHouse that works.... or should work, if they know which end of the soldering iron to hold)

EDIT (again): It should come as no surprise that the remaining (sixth) pole of the modified pickup selector won't make the grade - any time you swap pickup leads, you need two poles.  At the least, I don't see any way to do it as currently wired up.  Perhaps I'm wrong, and another member here can see a way to make it happen right on the 6P5T.  We can only hope that such a person rises to meet the challenge....

EDIT (final for the night, I swear!): What would happen if you did this? S1a and S1b are jumpered on Pins 1 and 5 - remove them, they're redundant. All they were doing is grounding the common pin of S2c, but S1c wasn't passing any signal anyway, on Pos' 1 and 5. Now, if you were to remove S1c entirely, and hot wire across it, all 5 positions would have the fader, which is not desirable. Hence the remove of those jumpers - now you have the same effect as before. And S1c is now free to combine with S1f to make a polarity reversal switch for Pos 3 only. Try that, grasshopper, I think (negative emphasis on that last term) that this might work for you, but who knows, it's late at night and I'm no longer the smartest man in the room. (Not that I ever was, but I do like my delusions, you understand. )


HTH



sumgai

[Yogi B]

Jun 14, 2023 23:59:25 GMT -5 sumgai said:

S1a and S1b are jumpered on Pins 1 and 5 - remove them, they're redundant. All they were doing is grounding the common pin of S2c

Incorrect, they're also grounding one of the terminals of S2b, thus (in series mode) the common of S1e — thereby providing a necessary path to ground for either the bridge or neck in series mode positions 1 & 5. Nevertheless this is roughly along the lines of thought that I have progressed along, but instead starting at S2a.

S2a is redundant insofar as it's choosing whichever gang of the fader that's selected by S2c is connected to the correct 'end' of the (pre volume control) signal: 'hot' (the red net) or ground. If we relocate S1c to be between S2c and the rest of the blue net we can then directly (& permanently) tie each fader to the relevant point.

If we were to then to try to eliminate S1c, we'd find that the links sumgai mentioned above (whilst still being necessary in series mode) are the cause of the parallel fader being a shunt across the lone pickup selected in either position 1 or 5 of parallel mode. This can be worked around by connecting the 1 & 5 terminals of each of the two (S1a & S1b) poles to each other, then using one of the (now two) spare poles of the series/parallel switch to toggle the connection between S1b(1,5) and S1a(1,5).

This put me off-track of my original idea, which required two free poles on the series/parallel switch; each to bypass one of my two planned PFOoP capacitors. But currently we're down to requiring only a regular 4P5T (super/mega) selector switch. stevewf whilst I know you've already constructed the 6P5T switch, it'll be easier for anyone else who wants to give this a try (or future you in need of a replacement switch) — so sticking to a 4P5T would be preferable if possible.

---

At this point the circuit still had the same functionality as yours — there's still not phase selection for the neck pickup — but I noticed something, something that would bug me if I didn't at least attempt to avoid: in position 4, one of the middle coils is hanging from either: hot, via the parallel blender; or, the junction between the other middle coil (i.e. the one that's actually selected) and the neck pickup. This was an annoying self-imposed additional requirement, but I think after a few dead ends I have something that works.

The main aha moment was flipping the neck pickup with respect to the bridge for the top two poles of the 5-way switch, since it's the other two poles which handle neck the only time it's used in conjunction with the bridge. From that it then works out each of the middle coils can now have one end permanently grounded.

I've coloured the below schematic loosely based upon yours, but I have relabelled the switch poles so as to try to have adjacent poles share the same letter suffix where possible (the numbering remains the same: S2 is series/parallel, S3 is phase). For simplicity I've omitted the volume & tone controls.

A full truth table should be as follows:

Switches			Output
S/P	Phase	5-Way	Pickup(s)
Series	In Phase	1	B
		2	B × (MN + <Series Fader>)
		3	B × (N + <Series Fader>)
		4	−N × (−MS + <Series Fader>)
		5	−N
	Out of Phase	1	B
		2	B × (−MS + <Series Fader>)
		3	B × (−N + <Series Fader>)
		4	−N × (MN + <Series Fader>)
		5	−N
Parallel	In Phase	1	B
		2	B + (MN × <Parallel Fader>)
		3	B + (N × <Parallel Fader>)
		4	−N + (−MS × <Parallel Fader>)
		5	−N
	Out of Phase	1	B
		2	B + (−MS × <Parallel Fader> × Cap)
		3	B + (−N × <Parallel Fader> × Cap)
		4	−N + (MN × <Parallel Fader> × Cap)
		5	−N

[stevewf]

Jun 14, 2023 23:59:25 GMT -5 sumgai said:

While I can't read your mind, I'm able to offer some suggestions that might be useful, or maybe not....

1) Leave off of selecting which coil of the Mid to engage, and move S3 to act as the desired phase switch on either of the other two pups.  This leaves the Humbucker intact in the circuit, and hopefully that will be something you can live with.

2) If you must have a single coil operation in the Mid position, then replace that pickup as appropriate, and carry as in Choice 1.

3) Procure yet another switch, and place it on either the Neck or Bridge pup - leave everything else intact. (This can be a dead-stock push-pull on either of the remaining controls..)

4) Do away with the small filter cap on S3c, and use both that and (the currently unused) S3d to effect the phase reversal. At that point, your Truth Table becomes... truthful. From your point of view, this might make the most sense.


HTH

sumgai

sumgai, Thanks for the help! I appreciate both the time you've taken to understand my scribblings, and also your general approach with advice to would-be Nutz: teach how to fish. When I've got time, I'll give more than the quick glance at your suggested actions.

EDIT: Oh hey.... Did you mean that Pos 3 should always be out of phase, and that a switch should not be necessary? Then simply swap one of the pickups leads, permanently. But in doing so, I have a feeling that this won't meet your expectations when in Pos. 2 (or 4) - that combo will also be out of phase. I ask this because your diagrams both denote in text, but don't actually show, S3 as selecting phase. In fact, I almost forgot to say something, but a studious look at the Truth Table reveals nothing about Pos 3 being out of phase, either by permanence or by selection. I'm sure you'll agree that that's the kind of detail that would be helpful to others, when reviewing your diagram(s).

(Addtional reasoning: sometimes a casual viewer will "borrow" a diagram, and not bother to copy all of the surrounding explanatory text. It's nice to think that even if they never come back, at least they got something out of The NutzHouse that works.... or should work, if they know which end of the soldering iron to hold)

Good point, yes, I'll fix that (i.e. explicit phase result in pos#3 in the truth table) and edit. That also will happen a little later than now. So, to answer, No, I don't want the Neck/Bridge combo permanently OoP, instead I'd like to be able to switch the phase at will, hopefully using the same control that the rest of the phase swap uses.

EDIT (again): It should come as no surprise that the remaining (sixth) pole of the modified pickup selector won't make the grade - any time you swap pickup leads, you need two poles. At the least, I don't see any way to do it as currently wired up. Perhaps I'm wrong, and another member here can see a way to make it happen right on the 6P5T. We can only hope that such a person rises to meet the challenge....

Yep, that's my understanding: two poles to swap phase, barring some outside-the-box solution ("outside-Steve's-mental-scope"). And no, I don't wanna go back and make it a 8P5T!    Too much work, bulky result... [hijack]Though I did make a 8P3T (postimg.cc), and with a fader, it could mimic the two outer positions... but it seemed cumbersome when I tried it. It would be best, IMO, if the selector behaves like a std SSS.[/hijack]

EDIT (final for the night, I swear!): What would happen if you did this? S1a and S1b are jumpered on Pins 1 and 5 - remove them, they're redundant. All they were doing is grounding the common pin of S2c, but S1c wasn't passing any signal anyway, on Pos' 1 and 5. Now, if you were to remove S1c entirely, and hot wire across it, all 5 positions would have the fader, which is not desirable. Hence the remove of those jumpers - now you have the same effect as before. And S1c is now free to combine with S1f to make a polarity reversal switch for Pos 3 only. Try that, grasshopper, I think (negative emphasis on that last term) that this might work for you, but who knows, it's late at night and I'm no longer the smartest man in the room. (Not that I ever was, but I do like my delusions, you understand. )

At this point, I there's been another solution offered above in this thread, between sumgai's post and this response. Still, I feel it'd be worth my time to make sure I understand this suggestion -- while the circuit is still fresh on my desk -- while I concentrate mainly on the new diagram above.

Thanks!

[stevewf]

Jun 15, 2023 5:17:52 GMT -5 Yogi B said:

S2a is redundant insofar as it's choosing whichever gang of the fader that's selected by S2c is connected to the correct 'end' of the (pre volume control) signal: 'hot' (the red net) or ground. If we relocate S1c to be between S2c and the rest of the blue net we can then directly (& permanently) tie each fader to the relevant point.

If we were to then to try to eliminate S1c, we'd find that the links sumgai mentioned above (whilst still being necessary in series mode) are the cause of the parallel fader being a shunt across the lone pickup selected in either position 1 or 5 of parallel mode. This can be worked around by connecting the 1 & 5 terminals of each of the two (S1a & S1b) poles to each other, then using one of the (now two) spare poles of the series/parallel switch to toggle the connection between S1b(1,5) and S1a(1,5).

Lovely

This put me off-track of my original idea, which required two free poles on the series/parallel switch; each to bypass one of my two planned PFOoP capacitors. But currently we're down to requiring only a regular 4P5T (super/mega) selector switch. stevewf whilst I know you've already constructed the 6P5T switch, it'll be easier for anyone else who wants to give this a try (or future you in need of a replacement switch) — so sticking to a 4P5T would be preferable if possible.

Heck, yeah! I only built that 6P jobbie to try to brute-force my way out of a jam. As usual, "work smarter, not harder" is the way to go (and it becomes a matter of being smart enough to know whether being smart is the right answer). I'll happily put that modded switch back in the parts box, waiting for another assignment! Same with all my modded switches. Their reliability has yet to be proven anyway.

At this point the circuit still had the same functionality as yours — there's still not phase selection for the neck pickup — but I noticed something, something that would bug me if I didn't at least attempt to avoid: in position 4, one of the middle coils is hanging from either: hot, via the parallel blender; or, the junction between the other middle coil (i.e. the one that's actually selected) and the neck pickup. This was an annoying self-imposed additional requirement, but I think after a few dead ends I have something that works.

The main aha moment was flipping the neck pickup with respect to the bridge for the top two poles of the 5-way switch, since it's the other two poles which handle neck the only time it's used in conjunction with the bridge. From that it then works out each of the middle coils can now have one end permanently grounded.

Brilliant, brilliant, brilliant. Yes, I'd begun to rationalize my having left a middle coil hanging: "well, it's only a potential problem..."

I've coloured the below schematic loosely based upon yours, but I have relabelled the switch poles so as to try to have adjacent poles share the same letter suffix where possible (the numbering remains the same: S2 is series/parallel, S3 is phase). For simplicity I've omitted the volume & tone controls.

A full truth table should be as follows:

Switches			Output
S/P	Phase	5-Way	Pickup(s)
Series	In Phase	1	B
		2	B × (MN + <Series Fader>)
		3	B × (N + <Series Fader>)
		4	−N × (−MS + <Series Fader>)
		5	−N
	Out of Phase	1	B
		2	B × (−MS + <Series Fader>)
		3	B × (−N + <Series Fader>)
		4	−N × (MN + <Series Fader>)
		5	−N
Parallel	In Phase	1	B
		2	B + (MN × <Parallel Fader>)
		3	B + (N × <Parallel Fader>)
		4	−N + (−MS × <Parallel Fader>)
		5	−N
	Out of Phase	1	B
		2	B + (−MS × <Parallel Fader> × Cap)
		3	B + (−N × <Parallel Fader> × Cap)
		4	−N + (MN × <Parallel Fader> × Cap)
		5	−N

Wow. That's fast. I've been banging and scraping my head over this to quite a while now. Months! I'll take a closer look when time permits (this eve, Pacific Time). Meanwhile, thanks, also, for using my wire colors. It'll help when I compare the current scheme with the proposed one. And I'll probably transcribe it using the software I've adopted for recording schematics, which will also help me absorb more deeply.

PS: for that Red/Hot network, I've taken to naming that (internally/mentally naming it, that is) as the "pickup output manifold" when there's a series/parallel arrangement; it's where all the outputs are first, finally, on one network. That's a term I think of generally, not just this scheme. Maybe that terminology will trip me up one day, but so far, it's ok for me.

PPS: I'm gonna hafta see how you made that HTML table work nicely. My efforts so far have been frustrated, with jumbled blocks and difficult-to-navigate BBCode.

Thanks!

[stevewf]

After sniffing through until I understood it as well as I can, I implemented Yogi B's scheme, and I report positive results. The truth table is accurate, and the guitar sounds as predicted.

I'm especially pleased that it was designed with a normal Superswitch instead of a custom-made kludge. It also has potential to be applied to a Strat with normal-sized pickups (just with the middle pickup being a dual-in-a-single type) instead of P-90s, and with Fender S-1 switches instead of other 4P2T options; that would be a fairly stealthy mod.

I've posted about the assembled guitar here.

Thanks again for help, Nutz!