Adding a "Spin-a-split" to a series/parallel.

[asmith]

Hi folks,

Some might have noticed that whilst I wait for the capacitors to arrive for the Strat mod I was doing, I was attempting to draw up a dream scheme for two humbuckers.

The idea behind the two-humbucker scheme I had in mind was that I could have either humbucker in series or parallel, as well as having a single-coil option for each 'bucker on top of that. There would be no maximum to how many switches and pots involved - this is going to be a big Switchocaster. Originally, I was going to do it with a super-five-way switch, with the extreme positions of the switch (1 & 5) being the single coil options. However, having seen Pete's rather clever 'spin-a-split' option, I'd like to incorporate that into the design to achieve the single-coil sounds, instead of using the five-way.

I've fooled around in Photoshop with a few diagrams, but I can't seem to be able to come across a solution to this myself. My main problem seems to be that the 'spin-a-split' relies on the 'series wire' of the humbucker (A- and B+, according to John Atchley) to be connected on the wiper of the 'spin-a-split' pot, but separate on the series/parallel switch. I see that Pete's mod has a spare pole to be taken advantage of on his push/pull pot, but so far I've only found myself a mess instead of a solution. Could I please call upon the gurus of the board to help me with this?

So what I'm looking for is, a scheme for a circuit module in which a humbucker can be either in parallel or series, and the 'spin-a-split' coil tap can be included.

Thanks so much for your continued assistance, and your patience with the great unwashed!

A.

[JohnH]

You can have Series or Parallel, and have a spin-a-split active in series mode only. For that, wire a dpdt as usual for an S/P switch, in which two of the outer lugs are joined by a link (for series mode). Then wire a pot from there to ground to shunt one coil.

If howver, you seek to have spin-a-split work properly in both series and parallel, I suggest there are better uses of your time!

J

[4real]

I can't take full credit for the "spin-select" control (except the name perhaps) for HBs...but I am tinkering together a few ideas to make it kind of unique for the nutz...

It could easily be adapted to control 2 HB's with one control...splitting both at once like so...



This gives the basic idea and 'theory' of the basic control....

www.smitspickups.com/coiltapping.htm

As for the series parallel thing...not possible (I don't think) on one control and could cause some problems and possible 'dead spots' even with multiple switches. AND...I think the main thing is that the parallel option is kind of obsolete with the range of this control.

On some pickups the parallel thing can sound good...like on my recent LP for example...and noise canceling...but very similar to the split sound with perhaps a touch of the other coil 'spun in' for more 'body' on the "spin-select"...

...

The guitars been in constant use and that control is fantastic...but some more tinkering should get even more out of the idea over time.

At present I am using a 500K audio pot and the down position selects the 'sweeter' inner coil of the SD JB HB which I prefer.

However, this selects the coils ok with the pull...but the range is a bit skewed...it sounds much like the full HB after about 3 from the full split...and there are things one could do with caps to create a filter effect along the range perhaps...but some of the values might have to be adjusted to improve the 'spin' function...perhaps it needs a lower value pot or different taper but might be hard to find with the push pull function.

As it stands however, it does HB and either split very well with no visible change to the guitar and works a bit like a tone control, midrange boost and bright switch on the Hb alone.

I will eventually get some sound clips together perhaps..interesting the 'split' is nothing like 'half volume' when split with this SD JB in the bridge position...but different pickups have vastly different power and effect...might be worth hearing what yours sound like in that guitar if possible.

If you combined the split of course, both pickups would change with both spin and select functions

[asmith]

If howver, you seek to have spin-a-split work properly in both series and parallel, I suggest there are better uses of your time!

If only I'd listened.

That's one DPDT (presumable a push/pull pot) for the spin-a-split, and one for the series/parallel. I think the above should work - I haven't tested it physically, but I've been through all the switch arrangements and in my own twisted little theory I think everything's good. Welcome back John, good to hear your move went well. Thank you for your help - your solution to the series mode was a great kick in the right direction.

But if Pete's right:

I think the main thing is that the parallel option is kind of obsolete with the range of this control.

Then all of this shouldn't matter. It was a fun exercise anyway.

[newey]

It was a fun exercise anyway.

Or, you could build it and verify that it works.

At first glance, your diagram looks all right, but I'm definitely going to have to go through it more thoroughly, not sure I fully see all that's happening there.

(This is my lack of knowledge showing, not a problem with your diagram . . .)

[asmith]

Gracias Newey. I don't know if you saw the old schematic or the new one though. To explain: the old one had a 3PDT controlling the series/parallel, until in a flash I saw I could do it with a DPDT and quickly edited the diagram before (I hoped/thought) anyone noticed.

I know it's a little naughty, but I figured I could get away with it. Just in case you took a second glance at the diagram and wondered if you had double vision before.

[4real]

;D well done

I meant possible on the single control I guess...

One of the benefits of wiring this guitar 4 times (!!!) and with different pickups originally is that I got to hear the thing with various options.

So...in this guitar (mahogany strat) and with a SD JB (renown for a good split sound apparently)...I ahd it wired to a standard series parallel P-P just before this rewire. Barring that I might have done something wrong, the sound was a bit different, but not that much...even the 'power' wasn't that different being much the same loudness...hmmm

In split mode you are "sampling" just the location of the different coils...so quite a different thing...effectively you are able to move the coils very close to the bridge or quite some distance away...with the spin function you are able to 'spin in' a bit of the other coil...

So...you can spin in with the sweeter single 'inner coil' some of the closer bridge coil bite...or conversely dial out and make sweeter the thin bright close coil depending on the switch mode. You are also spinning in noise canceling in the process. Once on full HB you get that big midrange boost...surprisingly though, it isn't excessively "louder" so much as fuller and midrange heavy.

On my LP there is both the split and parallel in the bridge pickup on the twenty-dual thing. I was very impressed with this parallel sound on that guitar and pickups. For one thing it is noise canceling and sounded very similar to the split sound...so perhaps on that guitar that would be preferable. The pickups are no-name high output HB's...so, they are probably a bit excessive in the muddy frequencies and sound good parallel. With the treble bleeds on both volumes, turning down cleans and brightens things up a bit.

So, I was impressed with the parallel sounds on that guitar and am kind of particular about having a very quiet guitar as far as possible...all my "working" guitars are fitted with HB pickups of some kind, even the 'single coils' which are SCn's or "noiseless" models.

So...depends on the guitar and the pickups and what you are after.

Personally I love the idea that there are lots of options in a guitar and that they are 'useful' or inspiring to have in there...a different sound might inspire a new tune or technique.

But...these days I am keen that the thing looks and operates in a clean and practical way. Even though my strat has a huge range of sounds and they all sound pretty good (some of the phase things are a bit excessive perhaps)...all these are 'hidden' and the default mode are the 5 or so sounds I'd want most from the thing.

In playing this new guitar and this control a lot in recent days...I am finding that I am using this spin-select control a lot. Generally I have the spin a little bit off full split (the pot is a little too sensitive) and this gives a good balance with the other pickups and a fairly trad SC strat sound...the middle selection a great tele like n+B combo. But it is easy to use the control to give a boost and HB midrange power for say a lead thing.

It depends on what you use a guitar for...in my situation and most people I suspect...I'm probably learning a tune, reading a lyric sheet, following the bass player and running on automatic...I can't be making complicated pickup selections too much.

I suspect in use I'd be favoring the B+N middle position...adjusting the spin control to taste and song...using the B+M for that stratty quack and a lighter rhythm tone or fills...switching to the bridge alone for lead as required. The B+M+N has a lovely acoustic quality, so I might use that and use the mode switch to move between that and the much louder bridge alone for lead with one switch...that's one of the beauties of the MR scheme.

So...you know...probably a good idea to examine and even try these sounds and choose a selection that is neat and easy to get to and use...adding more switches tends to clutter things up and make things trickier in practice...may even make the guitar less practical!

But you know...perhaps you like the idea of a lot of switching and knobs...so go for it!

Not sure of the actual guitar and pickups you are working with which can make a big difference...perhaps a good idea to actually wire up the things in different ways to see the basic sounds and combinations.

With the series mode things, they are much thicker and louder and a lot of bass, a bit much for my ears generally, perhaps I will tone those setting down some how though they have their uses I'm sure.

The reason for having cheaper but good guitars is that I can have a few...the common factor is the feel and action that I like, but the pickups and other factors are quite different...rather than too many options at ones disposal, I prefer to change guitars for that session (I only ever take one)...and this is extremely useful for when I feel in a bit of a rut playing wise (like trying out guitars in a shop can do).

I've had 'switch monster' guitars before and not found the same effect by simply changing the 'sound' of the thing with switching.

Plus...technique will have so much more impact on 'tone' and sound than any switch can produce...and there is only so much that you can expect one guitar to do well I suspect.

[asmith]

Pete,

I can't be making complicated pickup selections too much.

Neither me when on the fly, but with this Switchocaster I plan to make a guitar that I can set in a mode beforehand - I'm a primary tunesmith, so I'd choose what tone fits what song for me. Jamming should be interesting - I guess it's just a matter of learning the positions. Hell, I can touch type, surely I can switch a 'caster, right? Famous last words.

Regarding pickups - I'm in complete agreement with you. I can't expect everything out of two humbuckers on one guitar. Getting stuck in a rut usually isn't an issue for me - I have a piano for that. Should money roll in I'd definitely buy/build more guitars with different pickups for different sounds.

However, you'd better be damned sure that I'd wire them up all crazy. I simply want as many possibilities out of two 'buckers as I can fathom as possible and practical. Plus since I'm carving and routing the body of this beast myself, I can make it look as nasty as possible. After all, I think this is one of the sexiest things to grace the face of the Earth. And I really want a guitar full of switches where I can hit a 3PDT Stompbox Switch for 'solo mode.'

I am well up myself, you see.

[4real]

I'm with you on EVH's guitar...except that is the opposite of a switch monster, one pickup and a volume control marked "tone"...

Even though I am more 'moderate' these days...at least from the outside and ease of use, all three of my main guitars are trick wired.

The new "strat" is HSS with over 30 settings hidden in it, my last one a LP looks more minimal than stock but contains the twenty dual scheme in 4 push pulls on two HBs, and my tele that was/is my main guitar has only a three way and phase switch...but a sustainer as well...so I am not completely non-nutzy

I find that changing a sound can inspire a different kind of play, even if eventually I'll play something with a more usual tone...of course with recording these things can be useful too and real time operation isn't an issue.

There is a problem with the two HB scheme though...they can't do it all...splits and parallels tend not to be anything like or as good as a true single coil and even these can vary greatly...and there is a huge variation in HB choice...so no matter how much you switch things, there are going to be compromises along the way. A good splitting HB may not sound so great as a full HB if overwound or something for instance...quack can only really be imitated generally.

Still...I have a project in the wardrobe awaiting motivation (like I need another guitar)...the more I think about it the more outrageous the ideas are...was thinking perhaps a whole lotta lipstick pickups for added chrome for instance...since it has the most ridiculous gold metal flake all over finish I've yet seen. Something for if I ever take up rockabilly perhaps!

I quite like the idea of the PRS 513 kind of thing...5xSC and three 'modes'...but I kind of have that kind of thing in my strat...but it is a bit like a swiss army knife these things, useful, but not the easiest to eat dinner with and sometimes you can create a monster that doesn't do anything really well...I know, cause I have made a few 'dogs' out of otherwise decent guitars maybe I should redo a few of those as well!

[newey]

I saw the first one with the 3PDT. I'll have to start over I guess , but it definitely simplifies things.

EDIT: Had a look, and I think it's good! Although, let's let someone else vet it just to be sure . . .

I see that you have the Spin-A-Split wired in 3- conductor form in parallel and in 2-conductor (Rheostat, innit?) form in the series mode. I believe that is the correct way to do it for the series setting, but again, someone needs to have my back on this.

[ashcatlt]

Here's what I'm seeing:

In Series mode, with the other switch down, the pot works to split to one coil when turned one way and the other coil when turned the other way. You should get full HB in center position, though with half the resistance of the pot across each coil. That part kind of freaks me out, but I suppose if the total pot R is big enough... It'll probably want to be a linear pot, and a center detent would be nice too.

In Parallel mode with switch down, the pot splits to one coil turned one way and you get the full HB when turned the other way. So the pot works a bit differently depending on the mode switch and in parallel mode you don't get to choose which coil you want.

With the switch up, the pot does nothing.

[4real]

I thought it looked a bit weird like that...on mine the 3rd leg of the pot is not connected so it splits at 0 and full HB at 10 (well, at the moment it is at about 4 so need to work on that) and the pull switch selects which split it uses.

Clever though that you were able to get the parallel and split together though...

[asmith]

Ash,

...I'm lost.

Here's what I'm seeing.

Blue is the positive signal coming from the South pickup in parallel, or simply the whole signal when in series mode.
Green is the signal coming from the North pickup in parallel mode.

Like Newey said, in Series mode, there's variable resistance to ground from the series link between North and South, like Pete's originally posted spin-a-split. But in parallel mode, the pot turns into a volume control, splitting resistance between the output and ground.

The third lug of the pot is only active as an output in parallel mode.

Is that right? Or am I way off the mark? I gotta be honest, the way the pot becomes a volume control in parallel mode - the 'input' and 'output' being swapped compared to a 'normal' volume control - was a bit of a push for my knowledge of electrical theory.

[4real]

I'm not sure...but with the resistor splitting the parallel thing like that are you not also looking at a big drop in volume over the amount you will already get with that mode compared to series...and that when you change mode the control will be in a radically different kind of setting and need adjusting?

It's an interesting solution but I wonder about the practicality...but then that's me...carry on!

[ashcatlt]

Yeah, no, sorry about that!

My brain was adding jumpers which aren't actually there.

[newey]

But in parallel mode, the pot turns into a volume control, splitting resistance between the output and ground.

No, I think Ash was right the first time:

In Parallel mode with switch down, the pot splits to one coil turned one way and you get the full HB when turned the other way.

The pot does act as a volume control in parallel mode, but only on the S coil, the N coil isn't wired to the Spin-A-Split at all in that mode. So, you get full N coil at all times in the parallel mode, and the S coil gets added in via the Spin-A-Split.

However, you will never get "full HB" in parallel because the Spin-A-Split will add resistance to the S coil even when full on, whereas the N coil doesn't "see" the pot in parallel at all.

Still might sound good, though. It's a little funky but may be worth a try.

[asmith]

No, I think Ash was right the first time:

That's what I meant. I'm a right Christmas Turkey. Now we're both on the same page.

However, you will never get "full HB" in parallel...

I don't mind! I can switch the spin-a-split off and on, and I think it'll be close enough to full when on for me. I'm more likely to be playing at 3-7 on the S-A-S than 8 and 9.

As per suggestion, I shall build it and test it. Merry Christmas.

[sumgai]

Dec 24, 2010 16:42:35 GMT -5 asmith said:

Blue is the positive signal coming from the South pickup in parallel, or simply the whole signal when in series mode.
Green is the signal coming from the North pickup in parallel mode.

Absolutely the correct way to analyze and diagram-out a signal path. Unklmickey and I have been the only proponents of this methodolgy since Day One - even ChrisK didn't do this. (Instead, he pronounced it as "an exercise best left to the viewer.") From time to time others here have done it on a sporadic basis, but not often enough that the rest of the membership has picked up on it.

+2 (just 'cause I can do that!)




sumgai

[ashcatlt]

In parallel mode, with the pot all the way up, the top of the two coils are in the same spot. They're in parallel with each other and the full resistance of the pot. In fact, it pretty much loads the one coil the same at all times.

[asmith]

S.G.,

Just seemed the sensible thing to do. The karma is kind, thank you, although it seems giving 'karma' on the board is reciprocal karma in 'real life'... whatever, I'll just take the damn compliment. Pick your own culture's version of 'Merry Christmas,' please!

Ash,

In accordance with your incredibly informative post, I'm still trying to work through electrical theory, especially resistances, because I'm a doofus. On a side note, you don't know how many weird looks you can get from friends when you're down the pub, and in a moment of conversation you interject that you finally understand 'input impedance.'

Well, maybe you do?

Are you saying I could be overloading the coils?

[JohnH]

This is looking quite interesting, and what is clear from all your posts is that you are a perceptive and inventive designer!

On this module, it is good how when you switch off the split mode, the pot is taken right out, with no loading on the coils and you get the full simple series and parallel sounds. That gives you the freedom to select the pot value to best suit the split action, without compromising the unsplit sounds.

In the split/series mode, most of the interesting tonal action will occur in the low range of pot resistance (with regard to the active part of the pot, between left and centre lugs). This suggests a log pot, to spread this range out as far as possible on the pot turn, and not too high a value, I suggest 250k.

But in split/parallel mode, the tendency will be for the action to be at the other end of the pot travel, which suggests a linear or even an antilog pot, because the main tone changes will occur with small resistances on the right-hand side of the pot (as drawn)

I think you can help to balance the series and parallel response if you add a resistor, and maybe a small cap (guessing 1nF to 3.3nF), in parallel between centre and right lugs. If you use a 250k pot, then I'd suggest the resistor is in the range 100k to 220k. These extra components only act is parallel split mode. Final guess, for pot, definately 250k, probably log as described above, to get the series/split working best.

All of the above is a guess, based on my own fiddling with series/parallel blending, YMMV!

cheers

John

[asmith]

Your response is quite interesting, and what is clear from all your posts is that you are a bloody genius.

I'd never even thought of parallel resistances between input and right lug, but it makes so much sense.