Help: Series/Parallel 3 coils

[stevewf]

Hi again, Guitar Nuts 2 people. Here's a quick puzzle that I haven't solved -- and which I also haven't proven unsolvable. Maybe someone here can help with either.

It's about three coils (Stratocaster-ish positions), a 5-way Superswitch, and a push-pull phase switch, to achieve certain coil combos. Specifically, I've been trying for these 5 coil combinations:

Desired (not in any particular order):

	Phase sw down	Phase sw up
1	B & M in series	B & M in series (in phase)
2	B & N in series	M & N in series (OoP)
3	B & M in parallel	B & M in parallel
4	B & N in parallel	M & N in parallel (OoP)
5	N single coil	N single coil

Achieved so far:

	Phase sw down	Phase sw up
1	B & M in series	B & M in series (in phase)
2	B & N in series	M & N in series (OoP)
3	B single coil	M single coil
4	B & N in parallel	M & N in parallel (OoP)
5	N single coil	N single coil

(so I haven't gotten Bridge & Middle in parallel; instead I have single coil selections).

For those interested, here's how I got there:

SPOILER: Click to show

(click the images for larger versions, hosted on postimg.com)

Wiring diagram:

Schematic:

Anybody here wanna see if they can design a solution that'll achieve the "desired", above?

Constraints: I wish to use a 5-way blade switch and two pots, one of which may have a push/pill switch (cavity depth dictates that only one may be P/P).

Or, can somebody show that it's impossible, given the constraints?

Thanks!

[JohnH]

It looks like you're close ( I haven't checked the diagram though). Have you thought about a Fender S1 switch pot instead of a normal pp switch? It's a four pole switch on a pot and the extra two poles might let you get those phased settings. Obviously, it fits in a Strat too.

[stevewf]

Thanks for the idea, JohnH, I'll see what I can cook up using an S-1.

[sumgai]

Steve,


If you're not starting here:


The Original Mike Richardson Strat Wiring Diagram


then you're banging your head against the wall, trying to reinvent the wheel.  While Mike's diagram isn't exactly what you want, it's easy enough to figure out where to make the changes to fulfill your wish-list.

HTH





sumgai

[stevewf]

Thanks, sumgai, for the link. Somehow I'd been missing that whole thread (Mike Richarsdon's Strat). Looking into adopting/adapting it.

[stevewf]

I've banged my head against previous designs and the coconut husk (brain) was unable to get what I wanted. Which was:

	Phase sw down	Phase sw up
1	B & M in series	B & M in series (in phase)
2	B & N in series	M & N in series (OoP)
3	B & M in parallel	B & M in parallel
4	B & N in parallel	M & N in parallel (OoP)
5	N single coil	N single coil

So I scrapped it all and rebooted. I think I've got it. I'm hoping the kind folks here will take a look:

SPOILER: Click to show

If anyone ever wanted to see how I came up with it, here's an attempt at an account:

SPOILER: Click to show

First I drew five separate schematics corresponding with the five selector switch positions, first drawing only the in-phase ones, then adding the out of-phase ones in a different color. From those I saw two things:
-That in combos involving the neck coil, I could use a DPDT to choose which of the other coils to combine - either the bridge coil, or the middle OoP.
-That I could choose to permanently ground either the bridge coil or the neck coil, and use the five-way to swap the phase of the middle coil. But this 2nd choice was a trap.

Eventually I realized the I could fix the phase of the middle coil and twiddle one of the others using the 5-way; in other words, permanently ground the middle coil... but which of its leads should I ground, hot or cold? Meanwhile I was faced with a lack of poles in the 5-way, until I settled on hanging a coil on the hot. I chose the neck coil because it's got less wire in it to pick up hum (actually, I chose it by accident, then chastised myself for rationalizing it with the hum argument... and then after all realized that I'm wrong, I'm right, haha).

Choosing to hang the neck on hot also chose which of the middle coil's leads should be soldered to ground: the hot lead. It also meant that it's the bridge whose phase gets swapped by the 5-way. From there, it got easier.

Looking back, I see that Mike Richardson's Strat also hung a coil on hot. So maybe I could have taken a path that stared there.

Anyway, I'd appreciate a looking over of this diagram above to spot problems or suggest improvements. Thanks -Steve

[Yogi B]

Jan 30, 2024 3:04:15 GMT -5 stevewf said:

Anyway, I'd appreciate a looking over of this diagram above to spot problems or suggest improvements.

Your diagram should work as you describe.

One thing I noticed at the start is that one pole of your DPDT is redundant: if you connect s1b terminal 2 to s1d terminal 4, s2a could then be removed. (Otherwise, yes, the diagram )

With a spare pole on s2, I thought it might be possible to eliminate having the neck hang from hot, but I've had no luck. The two options I can see both involve 7 poles, either: the DPDT phase switch but a 5P5T selector switch; or 4PDT phase switch, which would then leave a pole unused on the superswitch.

There was another interesting variant where the phase switch flipped both middle & bridge at the same time and so avoided flipping the bridge phase back and forth across the 5-way (that is, in the in-phase setting, all pickups would be "phase A"). However that wasn't an improvement (aside from perhaps being slightly easier to wrap my own head around): it still had the neck hanging, but in addition shunted (to ground) the unused coil in positions 2 & 4.

---

Since you did say "not in any particular order" in your OP, what about a series/parallel switch rather than a phase switch?

Then it'd be pretty straightforward to get the following positions (with only a DPDT + superswitch, and without any hanging or shunted coils):

	Series	Parallel
1	B	B
2	B × M	B + M
3	B × N	B + N
4	N × −M	N + −M
5	N	N

(Since there was an extra position, I took the liberty of making it bridge-only to make the positions as symmetrical as possible.)

[stevewf]

Jan 31, 2024 22:06:34 GMT -5 Yogi B said:

Your diagram should work as you describe.

One thing I noticed at the start is that one pole of your DPDT is redundant: if you connect s1b terminal 2 to s1d terminal 4, s2a could then be removed. 

Thanks very much, @yogi, for yet another helpful review. Just in time; I was about to plug in the soldering iron!

Hmm... so with a freed pole, I could get the bridge coil alone in position 1 (albeit by shunting Middle to ground).

Since you did say "not in any particular order" in your OP, what about a series/parallel switch rather than a phase switch?

Then it'd be pretty straightforward to get the following positions (with only a DPDT + superswitch, and without any hanging or shunted coils):

	Series	Parallel
1	B	B
2	B × M	B + M
3	B × N	B + N
4	N × −M	N + −M
5	N	N

(Since there was an extra position, I took the liberty of making it bridge-only to make the positions as symmetrical as possible.)

OK, now this one looks juicy. It has all the settings I wanted plus more, without hanging or shunting. I'll definitely have to look at this. Thanks again!

[reTrEaD]

Feb 1, 2024 13:10:59 GMT -5 stevewf said:

Since you did say "not in any particular order" in your OP, what about a series/parallel switch rather than a phase switch?

Then it'd be pretty straightforward to get the following positions (with only a DPDT + superswitch, and without any hanging or shunted coils):

	Series	Parallel
1	B	B
2	B × M	B + M
3	B × N	B + N
4	N × −M	N + −M
5	N	N

(Since there was an extra position, I took the liberty of making it bridge-only to make the positions as symmetrical as possible.)

OK, now this one looks juicy. It has all the settings I wanted plus more, without hanging or shunting. I'll definitely have to look at this. Thanks again!

If you're interested in doing something like that, you might consider starting with the structure I outlined in Guitar Wiring Design Tutorial: Strat-o-Various Project pt1

[stevewf]

Feb 1, 2024 14:33:43 GMT -5 reTrEaD said:

Feb 1, 2024 13:10:59 GMT -5 stevewf said:

OK, now this one looks juicy. It has all the settings I wanted plus more, without hanging or shunting. I'll definitely have to look at this. Thanks again!

If you're interested in doing something like that, you might consider starting with the structure I outlined in Guitar Wiring Design Tutorial: Strat-o-Various Project pt1

Thanks for the link, reTrEaD. I'm gonna try using the layout straight from the post!

BTW, I like to lay a clear plastic sheet over hardcopy - hardcopy like the printout I'm making of your layout. Then I use dry-erase pens for drafting. That way, when I wipe it ut, I wipe out only the wires; the components remain for the next draft. When erasing, use a soft fibre cloth, or the plastic sheet gets scratches.

[stevewf]

Well, that was actually pretty easy!

I used reTrEaD's template (thanks!):

SPOILER: Click to show

Note: there's a capacitor that doesn't belong; it was an attempt to filter the Parallel OoP combo, but it also has an undesirable effect on the serial combo. I took out the capacitor after checking the 10 switch combos.

Then I translated it to my usual schematics software:

SPOILER: Click to show

The OoP cap has been removed

Here's a wiring diagram:

SPOILER: Click to show

For the curious, here's a photo of the guitar that's going to get this wiring:

SPOILER: Click to show

The pickguard will get holes for the pickups once I determine their positioning by testing. I'm hoping I'll get a good sound with positioning that looks more or less like a HS setup (2 coils near bridge, one near neck). The three holes so far: Master Vol, master Tone, Output jack.

These photos will go into a separate thread once the guitar's complete.

[Yogi B]

stevewf: you don't want to attach terminal 1 of s1d to ground as that'll short the output of position 1 when in parallel mode. Additionally, I don't see a particular reason why you'd want to keep the neck pickup permanently grounded (as it's not necessary to do so):

Also something else I've just noticed with you diagrams is that you tend to show a single coil's start wire going to hot, which is opposite to my expectations — and, as long as I'm correctly interpreting the magnetic polarities shown, goes against this convention (or so thinks my pre-coffee brain).

[stevewf]

Yogi B's got my back! Thanks, especially for spotting the ground short in pos#1.

Yes, neck needn't be permanently grounded, thanks for that one too.

As for convention and polarity, yes, I've been putting hot on the start wire --- actually, cold on finish -- only because of  post I read here a while ago that made me think that it'd be better to put the cold on the outside of the coil for its (albeit limited) shielding effect. Any opinions on whether that's a valid factor, worthy of bucking convention?

[sumgai]

Feb 5, 2024 11:28:35 GMT -5 stevewf said:

post I read here a while ago that made me think that it'd be better to put the cold on the outside of the coil for its (albeit limited) shielding effect. Any opinions on whether that's a valid factor, worthy of bucking convention?

Bucked Hum Is.

ChrisK (R.I.P.) said that, in his usual Zen manner, referencing the fact that a shield is still a shield no matter where the wiring starts or ends, because said shield is magnetic, not electrical.  

We give thanks for that fact, because manufacturers are all over the map when it comes to how to do things.  I mean, they might wind one model of pickup in one direction, and the next model they bring out could just as easily be wound in the opposite direction.  North and South are interchangeable simply because they're reference labels, and not standardized at all.  Ditto for Start and Finish, just more labels.  And don't get me started on wire colors, that's especially onerous in terms of companies trying to "out-confuse" buyers/owners/modders/etc.  One ring to bind them all?  Don't make me laugh.

Hey, you asked for opinions.

Now for your kicker - your use of 'cold' as in putting it on the outside is only an instantaneous point in time.  It'd be true if everything here was DC, but we're dealing with AC, as in frequencies.  At that point, you're no longer in "strict reference-ville", you're in the ever-changing world of a signal swinging between positive and negative across some reference point, ad finitum.

Magnetic theory is actually pretty intense.  We've covered it here, sometimes deeply. You can use the Search button above to look around for those threads.  And of course you can really go off the deep end with a more generalized search across the web, that's on you.  But you might also want to visit this link, just for grins:

Search results for Lightwave Optical Pickups for guitar and bass

HTH





sumgai

[stevewf]

Feb 5, 2024 12:30:31 GMT -5 sumgai said:

Now for your kicker - your use of 'cold' as in putting it on the outside is only an instantaneous point in time.  It'd be true if everything here was DC, but we're dealing with AC, as in frequencies.  At that point, you're no longer in "strict reference-ville", you're in the ever-changing world of a signal swinging between positive and negative across some reference point, ad finitum.

Magnetic theory is actually pretty intense.  We've covered it here, sometimes deeply. You can use the Search button above to look around for those threads.  And of course you can really go off the deep end with a more generalized search across the web, that's on you.  But you might also want to visit this link, just for grins:

Search results for Lightwave Optical Pickups for guitar and bass

Thanks, sumgai. I have much to learn. This includes more carefully checking my own schematics before moving onward. For now, I'll focus on that, as it's standing directly between me and a guitar that works. 

[Yogi B]

Feb 5, 2024 12:30:31 GMT -5 sumgai said:

a shield is still a shield no matter where the wiring starts or ends, because said shield is magnetic, not electrical.

I'll sidestep the issue of whether the shield in question is actually intended as defence from magnetic or electric fields by instead pointing out that we're specifically talking about the copper making up the outer turns of a pickup coil, which (along with any other shielding method you're likely to find in a guitar) is conductive. And, as such, is beholden to shuffle electrons about in response to external electric fields — in fewer words: is an antenna.

So now (and, since being a section of coil winding already answers if it's even necessary to connect it to the rest of the circuit: it unavoidably is), the question is: at which point in the circuit would we prefer to dump the noise from that antenna? Either: the 'hot' end of the pickup, with a relatively high impedance to ground; or at the 'cold' end, with a lower (typically much lower) impedance to ground. The answer should fairly obviously be the latter. However, before jumping to conclusions, there are two or three further things that need to be addressed.

Firstly, do the outer winds actually provide effective shielding (against electric fields) to the inner winds? If not, then every section of the coil would be equally susceptible to this kind of noise injection and make the above argument irrelevant in the choice of inner or outer as hot.

Second is the fact that the pickup's pole pieces most definitely do have a lower impedance coupling to the inner windings (than to the outer windings) — either in the form of capacitive coupling or, in the case of winding on to bare magnets and compromised insulation, direct electrical contact. If the poles are themselves grounded the latter case would cause a short between the inner windings and ground, which is obviously a much bigger problem if the inner windings are supposed to be the 'hot' end of the coil. Alternatively, leaving the poles ungrounded advances them up the list of potential noise sources, noise that would be more strongly coupled to the inner windings.

The third thing is then weighing up which is the lesser of two evils.

---

Ditto for Start and Finish, just more labels.

Unlike the others that one is pretty much set in stone — it'd be difficult to wind a pickup coil starting from the outside and working inwards. (Better to swap it for clockwise/counter-clockwise instead, which is dependent on the observers perspective.)

[stevewf]

Here's the latest attempt, v1.5S.

In addition to adopting Yogi B's drawing, it also taps into some Broadbucking when in serial mode - inspired by JohnH's Strat SP. I hope I got that right as well.
I hope the pretty colors don't distract.

SPOILER: Click to show

About the 47nF cap I added, inspired by the Strat SP:

Dec 10, 2010 5:19:36 GMT -5 JohnH said:

Enhanced tone control

A feature I have used on several designs is to use the third leg of the tone pot to bypass one coil via a capacitor, when in series mode. This is best if it is the more bassy coil, and it lets the highs from the non- bypassed coil become more prominent, making the tone brighter, while keeping a full bass signal. On a Strat, this is tricky to configure for all combinations, since it may be the neck or the middle coil that is wanted to be bypassed. But here, it can work in all three series combinations. It works in a consistent way, because as you turn up treble, it just keeps getting brighter, all the way up to 10

Via a cap, it shunts to ground part of the signal from the first coil. If I understand, that's the idea in a broadbucker - letting through the brights from single-coilage and leveraging the hum canceling from Humbuckerosity. I gave up the No-Load pot in favor of the enhanced tone control. Rationale: after all, there's a lot of single and parallel coil combos in this guitar, so a No-Load might be a bit bright without fiddling... or it won't make enough difference to matter anyway.

About getting a free drawing from YogiB:
Yogi gave me a fish this time, but don't fear; I did learn at least something about fishing as I feasted. I'll try to verbalize it:
I leaned on reTrEaD's "Guitar Wiring Design Tutorial: Strat-o-Various Project pt1", specifically viewing the pickups in layers, and using the poles of the 5-way to determine which pickups go in which layers, and then using a DPDT to manipulate the series/parallel relationship between those layers, but I was getting it wrong. Then I saw that Yogi's drawing made a pair of exceptions: positions #1 and 5, which correspond to the single-pickup selections. In those, the pickup in question's cold lead is in one layer and the hot lead in the other. This has the effect of bypassing the series/parallel switch and enables isolating the other pickups out of the circuit. I pat myself on the back for understanding it in this manner. Now let's see if I can remember to use it when appropriate.

So I whipped up this wiring diagram, too (read: I toiled laboriously, cursing the computer):

SPOILER: Click to show

More pretty colors, but real this time. I don't yet own the "safety cap" (330nF/600VDC), so for now the ground wire will bypass it. I don't gig, and my setup's been checked; I feel safe. That being said, if my account goes silent after this...

[stevewf]

So I wired it up accordingly, and I could now choose the location of the pickups, and make holes in the pickguard. Since I wanted to be able to move the pickups around freely while experimenting, I made a temporary "pickguard". Actually, it's a tape guard; the pickups are held in place by two-sided tape, and I didn't want that tape to be involved with the finish.



There are two pieces of clear acrylic screwed to the body, using the pickguard mounting holes. Then, each coil has a little acrylic carrier that gets taped into position.

Going in, I thought I would end up deliberating for a long time about where to place the pickups, but I quickly learned that pickup height has a huge effect on the sound - in conjunction with all the lateral (longitudinal?) positioning, there would be zillions of options to explore, so instead I found one that has good sounds, and called an end to the search.

One big thing I found: positioning the out-of phase coils worked better when it's neck and bridge (not neck and middle), so I simply swapped them in the guitar - without changing the wiring. One result that I want to change is that "Bridge only" is no longer true - it's "Middle only". So I'll get back in there and move some wires around.

Another lesson: the silicone-insulated, braided wires I'm using are a pain to corral into the channels toward the Superswitch when installing the pickguard. Gonna hafta figure something out.

[stevewf]

Revisiting this guitar, even though it's pretty recently "completed." Going back in because I've felt that the control setup is a bit of a compromise... and who wants that?  For me, the trouble is that the push-pull switch does series/parallel switching and the 5-way does phase switching, but I'd wanted that reversed. My stubborn brain had been unable to figure that out.

So I put my head back into the meat grinder, and I think, by George....


Yes, compromises have not been eliminated; to me these ones are more palatable, though.

My notes about the above:

• I like having a power sound quickly available, and that's why BxM is in an extreme position of the 5-way, and why the phase switch doesn't change it.
• I like having a broadbucker sound available, and that's why that "BB" capacitor is there, coupled with the tone control and the s1a pole. Still series-powerful, but brighter (thanks to JohnH and jhng for showing me how to use the tone control for that).
• I wish position#2 were reversed ("B" with phase switch down).
• I wish I could put something different on position#5, phase-up... keeping N involved but changing nothing else.
• Too bad I couldn't figure out how to get the broadbucker sound on the NxM and Nx-B series combos as well. I couldn't find a way to apply it to more than one of the series combos at a time.

I'm hoping the that Nuts will take a look and report mistakes, re-takes, tent stakes before I open 'er up and redo.

[Yogi B]

Apr 8, 2024 11:32:49 GMT -5 stevewf said:

• I wish position#2 were reversed ("B" with phase switch down).
• I wish I could put something different on position#5, phase-up... keeping N involved but changing nothing else.
• Too bad I couldn't figure out how to get the broadbucker sound on the NxM and Nx-B series combos as well. I couldn't find a way to apply it to more than one of the series combos at a time.

So, something like this:

[stevewf]

holy guitar nuts, beer nuts and deer nuts, Yogi B!

Haven't had time to really look - later this eve. You have a good track record in my book, so I'm optimistic of what I'll see. Thanks!

Oh yes, and as yogi saw, I meant "keeping N involved but changing nothing something else".

[stevewf]

Had a look at yogi's offering, above. Applause! I see three changes, one of which I feel I shoulda found myself, one which didn't matter... and one I wasn't anywhere near.

• Adding the broadbucking sound to the series/neck positions should have been obvious to me, as I'd already done similar for the other series position. I'd flipped s1a, so I should have seen the possibility of similarly flipping s1b.
• Flipping s1d has no functional consequence in this case (though it does help establish the local standard of "pickup lead gets pole").
• Changing where s1c/5 gets connected was not on my map. I needed a mental nudge to see that it could go where yogi put it.
• [oops, a fourth: the tone/broadbucker pot, done nice]
• [and a fifth: correcting the elec polarity of N]

This looks ready to go, and judging by the guitar's present set of sounds, these changes will make it very interesting, and, I think, the controls simpler to grasp, so it's going into the guitar!

When I have the time  

[stevewf]

An update for the curious.

Reminder of the guitar in question, which is now up & playing:


Reworked Yogi B's schematic:

SPOILER: Click to show

It helps me understand it better when I rework others' diagrams.

Wiring diagram based on the above:

SPOILER: Click to show

[Edit: corrected the pictogram, #5/Up]
Here I used colors of wires that I actually have on hand for guitaring.

Opinion:
I love this guitar. It makes sounds ranging from sparkling chimes to meaty humbucker, and forays well out into OoP.
The humbucker sound is quickly available at one end of the 5-way, regardless of the Phase push-pull position.
All of its two-coil combos are hum-reducing.
It does Series and Parallel combos of Neck & Bridge. OoP of those combos, too. Because the pickups are fairly well separated by distance, the POoP combo is not terribly thin, so I didn't feel the need to strangle either of the coils.
With the Tone knob at 10, the series combos are brightened by the "Broadbucker" cap; turn the knob to 9, and you get a more traditional sound (Parallel combos take the BB cap out of the circuit).
There are 10 different pickup combos -- no repeats, no dead spots. Yes, even the two Bridge humbucker sounds are slightly different from each other, because the BB cap is applied to one or the other coil, depending on the Phase switch (up is a slightly heavier sound, down is brighter).
It has an unusual three-coil OoP combo that works, albeit with some hum.
Even though it's from a kit, it plays very well. I upgraded most all of the hardware and electricals. Stainless frets, bone nut, massive trem block, carved neck joint, Tru-Oil finish. I've been able to get the action pretty low without buzz or fret-out on bends.

I call it a success. Thanks to Guitarnuts2 for the invaluable help.

Note: although it physically resembles the famous Jag-stang, its inspiration did not come from there; I had, in fact, never even seen that guitar until after I'd built this one! Also, its wiring is very different from that guitar, and it makes many more sounds.

[stevewf]

Oh yeah, and here's the underside of the wired pickguard

It's the first time I've wired with CTS pots, including the push-pull. Personally, I find these push-pull soldering eyelets a bit of a pain when you need to attach more than one wire there. Dismantling an earlier version, I broke an eyelet, so I had to scrap the whole pot for a new one. I've had less tragedy with Bourns push-pulls.