Logical S/P Switching with 3HBs

[shoogle]

Hello there, dearies.

I started fiddling with my guitar's innards about a year ago. This only concerns a small part of its wiring, but here's the problem:

I want to switch between all possible series and parallel combinations on my three humbuckers.

I've been using a modification of the 'Variation on the 94 sound wiring circuit' from www.1728.com/guitar3.htm to achieve this.

The problem is that the switching is very difficult to relate to logically, and other than memorising switch combinations, one is somewhat in the dark when changing sound.

What I'd like to do is be able to quickly understand what sound I'm switching from/to.

Currently I have 5 DPDT centre off switches to spare for this.

I can swap the switch type, but with eight switching pots and 16 other switches on the guitar, I don't have the 'real estate' to add anything more bulky.

I've had a few ideas as to how the switches might work logically:

s1= N in; series/ 2-way/ or 3-way parallel
s2= N out isolated (for eg. (N + M) x B)/ parallel
s3= M in
and so on.

Or by 'bus'(column), whereby N and M can be moved between bus 1 or 2, and Br can be 'bus' 2 or 3 - the other two switches can move the, ah, this doesn't sound very clear - I'll have to figure out some sort of drawing tool (recommendations?)

Any fresh ideas are likely to be more logical than mine.

[shoogle]

Hmm... Has anyone used programmable logic controllers and some sort of digital switchhing for this sort of thing?

What are PLCs like in guitars? Laggy? Bad for sound?

[newey]

Shoogle-

Hello and welcome! If you have already implemented the "94 Sound" variation, you're already a guitar nut!

The site, 1724.com, is run by our member Wolf. He will be along presently, and may have some suggestions to make your switching more logical.

But I think meaningful discussion of this will require more details of what, exactly, you have done. You indicate you did a "modification of the Variation". How does yours differ from the diagram shown?

with eight switching pots and 16 other switches on the guitar,

This is significantly more switching than shown on the diagram for that scheme, so it sounds like you have extensively modified the scheme.

Your scheme uses HBs, while the diagram is for SCs. Are you splitting the HB coils as well as series/parallel options?

I don't know squat about the use of PLCs in a guitar, that's a new one on me.

As far as a drawing tool, I just use MS Paint. For schematics, I downloaded the free version of DesignWorks Express, which works OK, except the files are in a proprietary file format, requiring a screen shot and importing into paint in order to get it into a .gif or .jpeg suitable for posting here.

[sumgai]

Mar 11, 2010 17:00:57 GMT -5 shoogle said:

Hmm... Has anyone used programmable logic controllers and some sort of digital switchhing for this sort of thing?

What are PLCs like in guitars? Laggy? Bad for sound?

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[glow=red,2,300]WINNER![/glow]

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shoogle,

Hi, and to the NutzHouse!

No one else here, except possibly the late and very much lamented ChrisK, as ever mentioned this possibility. I, being a former EE, do have an affinity for this methodology, but unfortunately, it goes against the grain of 99.99999999% of all guitar-playerdom to even think of digitally controlling their pickup selections. Sad, that.   Thus we are left with analog solutions that are bulky, cumbersome, unwieldy, costly, and worst of all, limited in their ability to adapt to solve new problems. Oh well, I guess we just make the best of it, eh?

I see that newey has ninja'd me, which means that he's already asked the remaining questions I would've asked anyways. We're all awaiting your further data input.........

HTH



sumgai

[shoogle]

How is it modified, ah...

I guess the biggest take from the diagram are the SPDT on-off-on switches, which were implemented on DPDT switches as a stop gap until I could think of something that might suit me more. I think I inverted the mid pickup from that in the diagram to alleviate phasing oddities.

2 <edit>SPDT</edit> switches are used per pickup to switch between North/South/series/parallel, and a DPDT to switch phase between the coils.

Then 3 DPDT centre offs to give each p/u an on/off/bypass(to master tone/vol).

Then another set of phase switches to phase the pickups with (or without) one another. (Actually, I used three switches for this (thinking that it would be easier to see the setting) - obviously, you only need two: perhaps there's an extra switch space for this change after all)

Anyway, then there's a volume/tone per pickup with a bypass switch (bypassing vol and tone) on each volume and two switchable tone caps on each tone pot.

Then the series/parallel switching plan from the 94 sound variation.

Then an on/off toggle (my favourite switch of all)

Then a master volume and tone (different pot values to the others, natch), again with bypass and a couple of caps.


I'll try to draw it, sometime soon. I think it will take a while. Perhaps I could take pictures to show what an awful mess I've made of my guitar.

I have to admit that I'm pretty hopeless with electronics, though. This was a way of practicing soldering and learning.

Effects pedals coming soon, hopefully, and an amp, someday.

[shoogle]

Which, I should clarify, means that the series/parallel section can be considered pretty much in isolation.

We have +, -

And N+, N-; M+, M-; B+, B-

--------------------Edit due to bad wording ------------------------------
The rest is pretty much irrelevant to this section of the guitar.

(as far as I can see, that is)

And hello, and thanks, and suchlike to all of you; kudos for a vibrant community and informative site - and a warm welcome, ta!

[newey]

Which, I should clarify, means that the series/parallel section can be considered pretty much in isolation.

OK, as I suspected, you have coil splitting, phase, switchable tone caps, which explain the number of switches. So, I understand your goal is only to simplify the switching in the series/parallel module, leaving the rest as is.

Restated, the question is how to simplify series/parallel selections of 3 HBs from the current 5 SPDT set-up (although you indicate you substituted DP switches, I assume the 2nd poles of each are not wired, correct?)

I don't have any ideas off the top of my head, this may take some collective cogitation hereabouts.

[wolf]

Well, I have finally arrived!! Yes, that is my website.

I never thought anyone would set up the "94 sound" circuit so that it would have even more switches.

Since newey has chosen to make a "stab" at a solution, I'll just see what he suggests as a solution.

[newey]

Stabbing blindly, perhaps! Suggestions are welcomed.

I guess the biggest take from the diagram are the SPDT on-off-on switches, which were implemented on DPDT switches as a stop gap

But:

Then 3 DPDT centre offs to give each p/u an on/off/bypass(to master tone/vol).

Since centering the On-Off-On series parallel switches (two per pickup for the M and the Br pups) presumably gives "off" as well, the individual on-off switches seem a bit redundant. Of course, you have the bypass feature on those switches as well.

I haven't fully thought this out, but as a "run it up the flagpole and see if anyone shoots at it" idea, you might:

Consider replacing the series/parallel module you have with a DPDT On-On-On for each of the pickups. This can be wired, if you wish, to give a coil split in addition to series/parallel for each pup individually, thus perhaps allowing some consolidation of your switching. Or, perhaps the middle position is an Off, and you then eliminate the separate On-off switches.

It would be more logical, since you could see, at a glance, whether the neck, for example, was in series or parallel with the others.

Basically, I think things need to be consolidated somewhat here, and I think there's ways that can be done while still maintaining the overall Nutziness of this "soldering exercise". ;D

[shoogle]

Wolf - thank you immensely for the website - it's been really helpful when trying to figure all of this out. It's a great reference, too (as is this site and the original guitarnuts).

Sumgai and Newey - and many more of you guys who post hereabouts - thanks for all the informative posts.

Restated, the question is how to simplify series/parallel selections of 3 HBs from the current 5 SPDT set-up (although you indicate you substituted DP switches, I assume the 2nd poles of each are not wired, correct?)

All perfectly correct! - simplifying the user switching whilst maintaining all series/parallel options (if possible) is the goal.

You could see it as a logic puzzle -
5 switches, DPDT or SPDT, on-on-on or on-off-on as you like
+, -, b+, b-,m+, m-, n+, n-.
to all those series and parallel options...
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And, actually, I hadn't really been considering on-on-on yet. Maybe there's an obvious solution...
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Consider replacing the series/parallel module you have with a DPDT On-On-On for each of the pickups

Given the mention of coil - cut, I take it that you mean the two SPDT + 1 DPDT on-off-on per pickup, not the five from the '94 tone'?

My bad for writing SPST - they are SPDT (no centre).

If so, in practice I find that the bypass here - though perhaps technically somewhat redundant - is actually really useful for flipping quickly to and from a 1 or 2 pickup setup from the '94 sound' section.

And the two SPDT setup I have is really easy to 'read' for the 'user' -

both up - coils in series
1 up, 2 down - N coil
1 down, 2 up - S coil
both down - coils in parallel

For ease of comprehension (and wiring) they're arranged toward the relevant pickup, too.

It's just the inter-pickup series/parallel that's hard to 'read' from the switches (that is, the '94 sound', not the intra pickup stuff).

No need for more coil-cut wirings, phasings, or anything - it all works as of now, and if it ain't broke...

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If, on the other hand, you do mean that I ought to replace the Series/Parallel from the '94 sound' with three DPDT on-on-ons, I don't see how that would deal with some series/parallel settings - eg. (N+M) x B or N + (BxM).

Still, I haven't really thought about using on-on-ons, I might well be missing something ridiculously, embarrassingly obvious.

But you are dead right that some consolidation is possible; there is already an off switch amongst the mess for each pickup.

The bypass has its uses, too - but I'd like to keep it separate.

Certainly, I'd be okay with turning a pickup or two 'off' before the series/parallel section to get some of the sounds I want.

I'll try to draw everything up (from my scribbled notes) over the weekend - I'm sorry for presenting all of this verbally.

And I have a vague idea involving four DPDT on-off-ons and an on-on-on - I'll look more closely and post it if it looks like it'll work.

[newey]

Sorry, shoogle, you had me a bit confused on the wiring here, I think I understand it now.

A diagram of what you have would be very helpful, however.

And the two SPDT setup I have is really easy to 'read' for the 'user' -

both up - coils in series
1 up, 2 down - N coil
1 down, 2 up - S coil
both down - coils in parallel

This arrangement is called "binary tree switching". My "in the works" "4caster Project" uses this style of switching to control 4 SCs in the same way as your 2 HBs.

In reality, the 5 SPDT switches for inter-pup series/parallel in your scheme are sort of a "binary tree on steroids" approach. What I was suggesting was using a single DPDT to give series/off/parallel for each pickup, (so 3 total). This can give all series/parallel/off combos of 3 pickups, and should be easier to visualize what you've got active.

But there are probably other ways to do this as well. The floor is open, gentlemen!

[JohnH]

Hi shoogie - Love to see a picture of this monster!

You have set out to get all possible combinations out of three humbuckers each with two coils, and to do that, there is necessarily considerable complication of wiring and operation - which is fine by me. Teat it as a tonal laboratory to find out which ones you like.

This was UnklMickeys assessment of these issues:

guitarnuts2.proboards.com/index.cgi?board=schem&action=display&thread=3160

If you can forgo the options of combined series/parallel sounds, and have whatever coils you select all in parallel or all in series, then it gets considerably easier to navigate and we have more than one version of the scheme that will do exactly that. It uses a dpdt for each pickup, just to select on/off, and a 4pdt to do series parallel. Before that, you can have your individual coil selection and phase switches as you describe.

Heres my version, as an extension to a Brian May 'Red Special'

Red Special with series/parallel

This was the discussion:
guitarnuts2.proboards.com/index.cgi?board=wiring&action=display&thread=4641&page=1

And on Wolfs site, he has this:

SuperStrat switching mod

John

[shoogle]

Thanks, everyone, for the help and patience.

Having read through the links provided, I've started to see quite how well informed you guys are!

I'm also beginning to see why ChrisK is missed so much.

Some of his plans are unbelievable, and clearly effortless for him...

Were I on terms with any deities, I'd pray and put in a good word.



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Anyway, this is my first attempt at a schematic (at least, since high school).

I haven't been able to incorporate coloured wiring, and I expect that I'd have to start again and use a layered schematic with LTSpiceIV, or just start again entirely with another program.

The below is the wiring more or less as first implemented, as best I can draw it. Sorry for the odd-looking switching potentiometer thingies - and the lack of many relevant values.


My thoughts for its future are to sacrifice the bypass function on the on/off/bypass for a parallel 'bus' and use two of the '94 sound' switches to decide bus start and end point on the series chain, the other three to turn the pickups on/off in series.

This could have the advantage of only engaging the 'per pickup' volume and tone when those pickups are in parallel (though they might still have something in series).

I'll try to think it out and post an update when I get some time next week.

Doubtless I've made many, and there are a few mistakes I've noticed in the process courtesy of other posts and threads - I presume that I ought to tie the earths on the first on/off/bypass (first 'centre off' from each pickup) to ground and switch the positive, rather than leaving things simply disconnected.

I also imagine that I ought to be using 500k pots for the master volume/tone, too - as they may face all three pickups in series.

And I'm not entirely sure that the whole volume/tone thing is right.

C10/11 are piezos, other capacitors are 0.33 and 0.66 microfarads. I did some extensive testing on this (not quite 'blind', but recording a crap riff over and over on a dry signal through 10 - 20 different capacitors and listening back without reading notes) and kicked myself when the ones I liked best turned out to be PIO.

I'll post the comparison files when I have the chance, and when I can figure out some audio hosting.

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Questions
1, Wiring - lower capacitance is best, yes? As thin a gauge as possible without sacrificing connection? 10/0.1mm?

2, I'm using LTSpiceIV, which is nice as it is free, allows editing of components, and will be able to run simulations if I ever get that far with electronics. Sadly, I can't see how to easily colour code wiring.
Does anyone have any advice relating to this program, Oregano, KiCad, Geda and other freeware circuit software? Is anyone aware of a study course or book that integrates the use of such software as a learning/testing tool and design aid?

3,My local solder club is running electronics classes using the "All New Electronics Self Teaching Guide" - whilst this does seem a useful book, most of the material was covered in my high school classes a good while ago.
I have forgotten much of it, and don't mind revising the stuff - especially if I plan to build anything more than a guitar circuit - but I'd like to be able to move on further. Any calls for literature pertaining to the use of programmable logic controllers, MIDI, and whatever I should really consider to be the next step from there?

4, I'm also aiming, in the indefinite future, to build a flexible little tube amp, and to modify the one I've got. I've been pushed toward Dan Torres' 'Inside Tube Amps' and 'The Ultimate Tone' by Kevin O'Connor. Neither is particularly available over here, and I'm having difficulty separating the many iterations of O'Connor's work. Which could you guys recommend?

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Thanks, one and all, and sorry for the long delays and longer posts.

[JohnH]

hi shoogie - that diagram is a huge piece of work - I can see you are taking this stuff seriously, so well done and +1 to you. If you have followed that through then you must be getting a good handle on this stuff.

On wires - it isn't very critical what wire gage you use in a guitar, so just go for practicality. For interconnects within the cavity, a stranded wire is easier to move around instead of a solid wire, but single plain bare tinned wire is good for grounds, but it does not matter too much, particularly if the cavity is shielded. For longer runs to a jack, or up and down the internal cavities of a Les Paul, I think it is better to use a shielded wire - again the type is not very important - the capacitance does not add up to much, much less than that of the cord to the amp.

I also use modelling programs, but have not tried LTSpice - I came across 5Spice which is another good freebie. I tend not to model the switches at all, just model the resulting connections of inductors and capacitors, resistances etc. When you run a model, you can get a very good sense of how tone may change.

The electronics learning around passive guitar circuits is all about how resistance, inductance and capacitance interact to change response. An exercise that I did, that was good for the soul, was to try to remember this stuff to a point where I could make a spreadsheet to model typical guitar circuits. Its here, and you may find it helpful:

GuitarFreak - Guitar frequency response calculator

Good luck!

John