'Slantbucker' Wiring Scheme?

[dugg]

I have a Grizzly kit that I use as a test axe. It's actually much better sounding than other 'strats' I have played. It has an alder body, rock maple neck with indian rosewood FB and abalone inlays. The PU's are low impedance (4._k range) with Alnico 5's. After recently rewiring it as a 'blender strat' with 7 combos instead of 5, I decided I wanted to get more radical. Since I've been a lifelong woodworker and already have 5 scratch builds (3 acoustics and 2 electrics) I have no fear of wood.

I chiseled the neck PU cavity to fit both the middle and neck PU's right next to each other, hard up against the bridge. Now the middle PU is where the bridge was, and the bridge PU is in the space that was between the old one and the bridge. The sound from the new bridge PU position is much, much brighter. That little bit of difference in spacing makes a big change in tone. As of now, the wiring is still 'blender strat' though I have switches on order from Stewmac that should be here in a day or so.

My plan is this. I'm going to consider the guitar as a two PU and wire it with a 5 position 'superswitch' so that I can get; Neck, Neck and Bridge in series, Neck and Bridge in parallel, Neck and Bridge in series out of phase, and Bridge. Then, I'll have a DPDT on,on,on wired to switch the two coils of the slantbucker to; Series, Parallel, and Single(probably the one closest to the bridge). I'm not asking for wiring help, I think I have it figured out. What I want to know is, am I missing something? Has anyone had some experience they think might make me change my plan? Thanks in advance!

[newey]

Dugg-

Hello and welcome!

You indicated:

I chiseled the neck PU cavity to fit both the middle and neck PU's right next to each other, hard up against the bridge. Now the middle PU is where the bridge was, and the bridge PU is in the space that was between the old one and the bridge

I'm having a hard time visualizing exactly what you did here. Did you mean to say that you chiseled the bridge PU cavity? Maybe posting some photos would provide a clearer explanation.

What I want to know is, am I missing something? Has anyone had some experience they think might make me change my plan?

Well, it sounds like you're already well on your way to implementing your plan and well past the planning stages if you're already a-chiseling out your pup routs. I will point out that putting your single coils closer together will serve to reduce the tonal differences between them. Putting your neck and mid pups together (assuming the mid is RWRP) and wiring them in series essentially makes a humbucker.

[dugg]

Hi Newey, thanks for the welcome! I just got the switches this afternoon, so I'll have to tear off the test pickguard and cut the new one and I'll get pictures then. I'm glad you asked because this is one of the more interesting parts of this mod, the cutting close to the bridge mounting area, that is. Also, I might have forgot to mention in my first post that this test axe has a trem bridge, which is what makes the question of closeness interesting as I'll explain soon. I guess I should give a little background first. A close friend of mine was one of N. Steinbergers' first employees in Bklyn. We were building instruments on our own as well, and messed around (even gigged with) Ned's 'plank', which was an early test axe that played horizontally and had about ten strings. After playing around with lots of pickup positions, we concluded that the most extreme positions (closest to the neck, and the bridge) were the most useful, simply because they were the most 'bassy' and 'trebley'. I recently finished a 'scratch built' NY style strat (for the same friend that worked for Ned). I mounted the bridge HB so close I had to carve a channel under the edge of the mounting ring so the front of the bridge could fit under it.

Naturally, this weakens the wood directly in front of the bridge, and since the grain is running exactly the wrong way to resist the pull of the trem bridge screws, something needed to be done. So, in both the NY strat and my grizzly test axe, I mortised in a block of hardwood as wide as the bridge with the grain running crosswise to the body. In the NY strat I used a rock maple block, in my test axe I used a chunk of composite bamboo floorboard.

On my test axe, I left the block about a 1/6" higher than the body. Since it's only supporting the first 5/8" or so of the front edge, the bridge can be rocked backwards for about a half step up in pitch. It also seems more stable when I'm tuning it than when it was sitting directly down on the body. Other than the fact that I planed it much flatter than the (finished) body is, I don't know why that would be.

The original alder body was machine routed for three PU holes, I assume in the stock position. The position of the bridge PU was about one pickups width away from the bridge, originally. I chiseled the hole wider in both directions. About a quarter of an inch in the direction toward the neck, and a whole PU's width in the direction of the bridge. Now, the hole is big enough for two strat PU's side by side. Slantbucker! It's interesting that the triangle tabs on the bottoms of the bobbins make it so that you must position them facing outwards, so that the PU's can get close. That limits how close you can get the bridge side coil to the bridge if you keep the PU perpendicular to the strings. By slanting that coil, you can get the poles close on one side.

I've already been playing with the old 'blender' wiring and the new PU positions for about a week now, and I really like it. The combination of the two bridge coils (in parallel) is my new favorite sound. Besides actually being humbucking, it has a 'humbucker' quality of compression while maintaining an amazing amount of brightness. The odd thing is that the two coils together seem to have a higher output than either alone, or than one of them and the neck PU. Odd because combining coils in parallel halves the resistance. Also, why is the combo of neck and one bridge coil a little quieter than the combination of the two bridge coils? Totally counterintuitive considering that it's well known that strings have less energy as you get closer to the bridge. I tested the resistance of all three coils months ago and wrote 'em on the bottoms. I'll see them soon, but if I remember they only varied from about 4.5k to 4.7k or so, with the hottest one at the bridge. I guess that could be enough to acount for some volume differences though, eh?

I'll start wiring up the super switch tonight, if I get to cutting out the pickguard there'll be pictures coming.

[newey]

DG-

The position of the bridge PU was about one pickups width away from the bridge, originally. I chiseled the hole wider in both directions.

So it was the bridge rout you were chiseling. Now I think I see what you have done here. You've got a neck SC with a bridge "humbucker" comprised of your mid and bridge pups, correct?

I mortised in a block of hardwood as wide as the bridge with the grain running crosswise to the body

I am not worthy . . .

I used a chunk of composite bamboo floorboard.

I like the sustainable/green thinking here.

[newey]

And since you already have one of those supermegaswitches, and you're apparently wiring it as I post, I assume you're not interested in this, which uses a std start switch:

SC and HB w/ Std Strat switch

But it might give you some ideas, especially ChrisK's note about capacitors . . .

[ashcatlt]

Welcome!

What was the question?

Well, anyway, on the subject of why the parallel position is louder than the single I'll offer ChrisK and Sumgai's posts in this thread. If you figure it out, clue me in okay?

On the question of why the 2 bridge pickups are louder than the bridge single + neck (that was part of what you were talking about?) I'd submit that the 2 bridge pickups are reinforcing each other in a very similar frequency range. That is, the overtones they are picking up are almost identical. The neck pickup gives you a different set of overtones, and some of these will be out of phase with those produced on the bridge. So the neck + bridge is more filling out the spectrum whereas the 2 x bridge is bumping the volume of a limited subset thereof.

[ChrisK]

on the subject of why the parallel position is louder than the single I'll offer ChrisK and Sumgai's posts in this thread

Again, a pickup is only an AC generator. The model is the generator (voltage), and the internal impedance which is the series resistance of the windings and the inductance of the windings as a coil inductor, in parallel'ish with the effective inter-winding capacitance.

You can, of course use a current model. If you recall the Thevenin and Norton conversion mechanisms (if you don't, first call them), a voltage source in series with an impedance is equivalent to a current source in parallel with the transformed impedance.

From a First Principles perspective, in electronics, current is the principle from which the others are derived. The basic unit is the electron and how many are passing thru in a second.

The DC resistance of a pickup coil, while a somewhat accurate indicator of the number of turns of wire in a pickup, and the relative output of a pickup, for exactly the same types of pickups only, is only accurately meaningful as the measure of resistance of the wire. Since a few different wire gauges are used in pickup coils, with the somewhat random actual resistance per unit measure of wire for any given gauge (+/-20% or more - it's awful dang thin guys), there is significant variation of little meaning in a resistance measurement, compared to the variation of significant meaning as it relates to gauge and the actual number of turns (since the inductance of a coil is proportional to the square of the change in the turns ratio.....).

This, coupled with the frequency response variations of the different magnet formulations and the varying production strength of the actual magnetization of each magnet, the DC resistance of the coil is only the accurate indication of the DC resistance of the coil. Based solely on a resistance reading, the DiMarzio HS series with resistance readings around 20+K should be scorchers but they are not. The Duncan Designed Scorcher, with a resistance reading around 20+K is.


The generator and its internal impedance:

A generator can develop its maximum output potential only when there is no load. When there is a load, a voltage divider is formed between the internal impedance of the generator and the external impedance of the load.

When the output of the generator is shorted, a maximum short circuit current flows that is a function of this internal load. In a sense of speaking (and a working model thereof) a DC battery (a collection of individual cells arraigned not unlike a battery of artillery - attributed to Benjamin Franklin) is really a device that generates a maximum potential (voltage) at all times, and only its internal resistance increases as a function of its declining charge. It appears to have no output voltage only since its internal impedance becomes infinite. A battery tester in effect creates said voltage divider and measures the voltage developed across only the external part thereof.


definition

I use the term impedance in its full meaning since resistance is only one component (and only real) part thereof. Real only means that its effect, by itself, can be represented in the real plane. For a full, accurate, and honest representation (which IS REQUIRED for any understanding approaching any degree of truth, accuracy, or meaningful insight), of impedance, the complex plane and/or phasor representation must be used.

Any attempt at understanding the actual effects in play within an AC circuit without a functional understanding of AC circuit theory will be no more accurate than describing the taste of various flavors of ice cream without actually opening the containers and tasting them.

While it takes an understanding of AC circuit analysis for all to fully "see" what is happening within a passive electric guitar, all having said understanding would make posting about it moot.

/definition


definition

Unit

The identity unit for any given object type. In mathematics this is usually one (or 1). For instance, the hypotenuse of a unit square (one with each side of length 1) is the square root of 2. This is a clue, what is the length of said model hypotenuse of a unit tesseract, a four dimensional "qube"?

For a pickup model, in its dimensionless form, it has an output of 1, and an impedance of 1. I didn't say "one what", they're just all "1".

/definition


For a DC-like analysis (I didn't say a DC only) one unit pickup coil is usually driving an impedance of 250K on both the volume and tone controls (we'll pretend that this is at a frequency where the impedance is the same as 250K) as well as the input to an amp. While we'd all like to believe that the input impedance of an amp is 1 Meg Ohms, it usually is not. A good value to use is 500K to make the math’s easy.

Our single coil pickup, in generally reality (not relativity), has an internal resistance around 5 to 8K Ohms. We'll pick 5K263.

So, the effective external load is 250K||250K||500K or 100K. This is being driven by a generator with 5 K of internal output impedance. The external voltage developed is 100K/(100K + 5K263 K) or 0.95 of the internal voltage developed (1).

Now, if we have two of these unit pickups in parallel, each developing exactly the same signal and voltage, we effectively are driving the same load with a generator having an internal impedance of 2K632 Ohms. This develops an output voltage of 100K/(100K + 2K263 K) or 0.974 of the internal voltage developed (1).

This isn't much higher, but the harmonic content from two pickups spaced apart is richer than from one alone, and most effective pickup amp and cable loads are really a good bit lower in impedance. The human ear hears frequency variation much better than amplitude variation. (This makes the whole tremo'Leo thing even more interesting since an effective variation of amplitude of 6% (one half-step in pitch) would have never been noticed. "Yo Sparky, what's that there shiny lever on yer geetar do? Oh, not much...")

The increase in the "width" of the sound is what we notice since, not only is the harmonic content fuller, the effective impedance of our combined "meta-pickup" is halved, with a resulting increase in the center of the response bandwidth of 1/2 octave.

The effective instantaneous output from two pickups in parallel is the average of their instantaneous output levels.


Having two pickup coils in series causes their outputs to add. It also causes the effective internal impedance to double. This is why 500K controls are better for such structures; the same current loading is effected. The added inductance results in the center of the response bandwidth being 1/2 octave lower, and, since most non-welding humbucking pickups are comprised of individual single coils that are generally "weak sisters" of their single coil counterparts, they need all the gentle loading that we can give them.

And again, this was all just DC-like cheating, things are really more complex..........


Ratios:

While the pickup spacing on a Strat is pleasing to the human eye, there is little other basis to said spacing. One might argue that the harmonic content along the string, solely as a function of sensing along a string for any given same plucked note, is based on the ratio of the distance from the bridge saddle. A coil placed nearer to the saddle than a traditional single coil, is likely between 1/2 and 2/3 closer. One would argue that the harmonic content is then 2:1 or 3:2 higher. The closer to the saddle, the higher the harmonic content, the lower the signal.

Piezo saddles sound the way that they do because they are sensing the strings at the, er, saddle. However, since they are sensing pressure variations and not string excursion, their output is higher than zero (but their internal impedance is most high).

This is why I preach selecting the bridge coils in a humbucker as a matter of the tone desired, and selecting the corresponding hum canceling coil in the neck humbucker only then as a matter of convenience. Of course, this is on a unit basis, slug coils sound differently than screw coils, even in a neck pickup (yada, yada, yada).


So, what you are doing has always made perfect sense since it's all just
physics anyway.


Good luck and happy routing. Remember, it's harder to put the wood back in......................

[dugg]

Hi all, thanks for the great welcome, I've really enjoyed reading other posts on this board in the last few days.

Newey, "You've got a neck SC with a bridge "humbucker" comprised of your mid and bridge pups, correct?" exactly.

I'm glad you approve of the sustainable wood angle. I've actually used a bit of bamboo in other guitars, and a young apprentice recently built a neckthrough in my shop with a bamboo neck. It sounds great. He also made the fingerboard out of Ipe, which commonly used for decking and is only about twice the price of redwood by the foot. Ipe is harder and heavier than rock maple and rings like aluminum.

Also, thanks for the link to that strat switch thread. I've wired up a similar thing for a big apple strat, with a 5 position switch, but it only had coil tap positions on 2 and 4 (if I remember right), no series. Hopefully, I'll be able to give that one you showed me a try soon.

ashcatlt, you're right that the two coils being closer together means that they pick up more similar frequencies, but the sound of the strings seem to change more dramatically as you get closer to the ends. I think you can hear a bigger difference in one inch movement if that inch is at the end of the string than in the middle. In fact, I'd say that the sounds coming from the new position are more 'different' than any of the three old positions. As a matter of fact, the sound of the two single coils of the 'slantbucker' were so different I actually had a hard time deciding which coil of the 'slantbucker' to use as the single on the DPDT series/single/parallel switch. I opted for the new position one because it was much brighter.

Oh, I forgot to mention, I got it all wired up last night on the scrap pickguard. Nothing to do now but cut the new pickguard out. My girlfriend left me her camera, so I'll take pics and post them in a few hours. The new sounds are AMAZING! There are 9 seperate combinations that use all three coils. The series sounds are hot and drive the amp nice. Also, I was mistaken in my previous post when I said the Grizzly coils were in the 4k range, they're around 5k. The neck PU by itself is 5.59k. Both bridge coils in series and in series with the neck gives a resistance of 15.8k! That sound is compressed and creamy but with lots of harmonic sensitivity as well.

I used J. Atchleys' t-riffic wiring diagram for the super switch and my memory for the DPDT. Atchley mentions somewhere that low impedence, clean sounding 'vintage' single coils lend themselves better to reconfiguring than hotter types. This is my first time messing around with the positions of strat type PU's, and I'm inclined to agree with Mr. Atchley. I'd like to add that they seem not only sensitive to electronic reconfiguration, but also to physical reconfiguration. This is one heck of a mod. I'm very, very pleased with it so far.

ChrisK, thanks for your illuminating post! BTW, I didn't let a 'router' come any where near my axe. And, I did put some back.....

[newey]

Dugg-

the sound of the strings seem to change more dramatically as you get closer to the ends. I think you can hear a bigger difference in one inch movement if that inch is at the end of the string than in the middle.

Yes, this is as expected. I think ChrisK made that point somewhere in that long post.

As far as sustainable woods, we've discussed that some, too. I just had my dining room floor redone with solid plank bamboo flooring, and I have 2 whole boxes left over. Hmmmm . . . .with some clamping and gluing I could get a body blank sized piece.

But I'll leave the chiseling to you, I'd have to rely on a router.

Anyway, glad you're happy with your mod, be sure to post some pix in the gallery.

[dugg]

Ok, it's been a few weeks playing the 'Coyote Dancer' now. BTW, I've apparently coined the term slantbucker (!). Google searches return only my posts as of now, you read it here first. On three different forums not one person has said, "Oh, I've seen a guitar wired like that....". Strange that only a few days hard thought came up with something this original. Original, and much more useful than the 'stock' setup. Shredder players seem to gravitate towards the slantbucker alone, usually with coils in series. Switching between the slantbucker and the neck coil gives a dramatic change in tone now. Reminds you why LP switches say R and L instead of N and B.

I have discovered one thing that I will change, though. Right now, when I switch the slantbucker to single, it's the old bridge coil, which is not RWRP to the neck. That means 3 positions are not humbucking, but could be if I swapped the two slantbucker coils. Since the coils have different resistances, my cursed bat ears will hear the difference. Hopefully, I'll like it.

Once again, thanks to all, this forum rocks!