Circuit/Layout Check: X-Blender, etc

[ozboomer]

'lo all...

Well, I'm being all inspired, once again... and although I like the SPlender mod I did with my Squier Bullet, I find the mod has a couple of significant problems -- 1) it's too complicated for me to use without having to bend my brain and 2) it's definitely too difficult to explain how it works to someone else.

Thus, I'm going to have another go at a simpler arrangement, both in terms of design and of how I might go about wiring it. The SPlender mod has fulfilled its primary function pretty well, in that it's given me a good idea about the sounds I might like... but this time, I'm going to have a go with a simpler blender mod (details to come).

...and the fact that I can grab a loaded pickguard for a reasonable price means I can have a number of "personalities" for my Bullet, just by soldering a couple of wires. Simple and yet flexible... hmmm...

For now, perhaps some of my learned colleagues could cast their eyes over this diagram, please:



I know it's drawn backwards ...and I intend to re-do it the "correct" way 'round... but it's supposed to be a standard/stock Strat layout; I think it's right but I still like to get another few sets of eyes to look at these things.

Once I've confirmed that the layout is correct, I'll work-out the wiring diagram... and then I'll do the same things with the new design. My intention is to come up with something that will have minimal wiring changes and yet will give me the variable blend combinations I'm after... Note that I already have the design roughed-out.. but I still have to create a "pretty version" for posting...

Thanks in anticipation, folks...


John

[ChrisK]

A (small) number of folk a'planet will be pleased to see that you've done the huge public service of drawing the schematic for a left-handed Strat. These are very hard to find a'web.

Leave it this way, who knows, it just might catch on. The electrons won't mind (or even notice).

And besides, if someone can't mentally translate this (or take a joke), they likely shouldn't be single-handedly (or even double-handedly) trying to operate a guitar regardless of any external influence(s).

[pete12345]

looking at this makes me realise how totally illogical the current standard strat layout is- the tone controls are coupled in the N+M position, the second pole on the switch is effectively redundant, and there's only two combined settings. The original setup at least made some sense, with separate tones for the neck/mid pickups, and not on the bridge (thus preserving all the treble)

Surely there's a better stock layout than the current one?

Nicely drawn diagram btw, and as to whether or not it's 'backwards'- surely the point of a schematic is that the position of components is irrelevant?

Pete

[ChrisK]

Surely the point of a schematic is that the position of components is irrelevant?

Well, certainly irreverent.

That's why so many folk have trouble with schematics; anything could actually be located anywhere.

Looking at this makes me realise how totally illogical the current standard strat layout is- the tone controls are coupled in the N+M position, the second pole on the switch is effectively redundant, and there's only two combined settings. The original setup at least made some sense, with separate tones for the neck/mid pickups, and not on the bridge (thus preserving all the treble).

Of course. The original switch was a true 2P3T one.

The cap could/should be shared since only one pickup could ever be on at a time. The bridge had no tone control since most amps of the day had the high frequency response of a hangover.

A small group of terrorists back in the 60's that were armed with needle files (who knows, the insurrection may have begun even earlier during the "beat" period) began to surreptitiously file "notches" into the mechanism of unsuspecting switches, thus rendering them "coupled" since this was a shorting (as in make before break) switch.

The result of this technological groundswell was the 5-way Fender lever switch (do note that Fender begrudgingly adopted it in the 70's). Whilst excessively coupled, the tonal enhancement was deemed desirable and the interactions acceptable.

The use of one pole for the tone pot selection was not redundant since the tone controls were oft turned down (ye gads, some early Fender instruments even had 0.1 uF tone caps) and inter-pickup interaction would/could occur thru the shared cap if the pots were directly connected to the pickups as well as the shared cap. Remember, the original focus was on clean, clean tone.

And, folk seem to keep buying these things.


Rather than being illogical, it's just unfortunately evolutionary. As Yogi Berra once said "if you don't know where you're going when you start out, you never know where you'll end up."

(Of course, he also said "when you come to a fork in the road, take it.")


Are there solutions to the problems of this solution? Yes, they are called the 4P5T lever super switch, the 2P5T lever semi-super switch, and the Schaller Mega Switches of forms many. Oh yeah, and GuitarNuts.

There are some mods that do clever(er) things tonal with the redundant pole.

[ozboomer]

The next installment begins...

Well, I've now done the "conventional" right-handed standard/stock circuit diagram... at least, I think I have it right, viz:

Now, to the idea of this "X-Blender"...

I think it's probably been done before... but I'm trying to do things with minimal changes to the stock wiring, so it's less likely for me to make a mess of things

The thinking is that we take the old idea of a "neck pup on" switch and put a pot on it, to allow us to wind-in the amount of signal coming into the mix from the pup. There's also nothing to stop us from doing the same thing with the bridge pup and we can use a simple switch to decide if we'll wind-in the neck or the bridge pup.

With this thought in mind, the first thing I did was to take the stock circuit diagram and make some breaks/re-use the existing "wires" and see if I couldn't make the thing work, viz:

Tidying-up the diagram a bit and re-working it, I came up with the following:

Now, I'd appreciate any thoughts about this (even IF! it is a re-design)... but I still have one more option I'd like to add-in... but have had no success in designing (yet):

If we add a single DPDT switch in some way to the circuit, would it be possible to select between a series and parallel connection for the added pup?

As I wrote earlier, the SPlender mod does some good things but it's too complicated to explain to someone. So far, this "X-Blender" is fairly simple to explain -- whatever pup is NOT selected by the 5-way is wound-in by the blender pot, except nothing happens when the middle pup alone is selected.

Anyway, I've been at this for some hours now.. and my brain is totally addled...

Lookin' forward to your thoughts, folks...


John

[pete12345]

That won't work I'm afraid- all that will happen is the volume will reduce as you turn the knob. All you need to do is wire a pot across the neck and bridge 'hot' wires, like this (couldn't find a schematic, only a pictorial version):


This does exactly what you want- blends in the non-selected end pickup in positions 1,2,4 and 5. In position 3 it has no effect.

Ideally, you should use a no-load pot for the blender, so it is out of circuit when turned fully off. You can modify the existing pot by taking off the shell and scraping away the end of the resistance track next to the unconnected terminal. It will work without, but there will always be some interaction between the pickups.

EDIT: alternatively, looking back at your diagram, you could make it work simply by removing the connection between the blend pot and ground.

[ozboomer]

I think I've seen that diagram before (the Fralin web site?) but had never analyzed it properly.

Doing so now, it seems we have a slightly different take on doing the blending with this arrangement. I think this circuit diagram is right:

It doesn't seem to be majorly different from my suggested scheme... but in this case, I think the "full signal" of the "other pup" is simply cut by the pot... but does this mean we'll have problems with a "floating" return? One advantage of this arrangement is that we free-up the other pole of the 5-way for some other use (to help us get the series switching as well!? .

With my suggested design, the "other pup" is actually shorted to ground, so we won't have that "floating return" problem.

TMTOWTDI

Any other thoughts on this... or other things?

[JohnH]

I think that diagram is OK. To get the smooth sweep of blending, Id suggest wiring the log pot (could be standard ex tone pot) so that the mixing happens at the 0-5 end of the pot where resstances change most gradually. The blending would be max with an anticlockwise turn.

For parallel blending like this, I find that it mostly happens between 0k and about 30-50k.

John

[ozboomer]

Well, the flood gates open now...

Mar 8, 2009 3:42:06 GMT -5 JohnH said:

I think that diagram is OK.

Which one, the original concept I posted OR my take on pete12345's blender posting?

In any event, is one of the two designs intrinsically "better" than the other? What about the thought on having the grounded blender pot? Is it a better/worse way to go than the "splitter" arrangement? Is it quieter? Does it do anything better with actually turning-off a pup rather than always having *some* interaction?

Mar 8, 2009 3:42:06 GMT -5 JohnH said:

To get the smooth sweep of blending, Id suggest wiring the log pot (could be standard ex tone pot) so that the mixing happens at the 0-5 end of the pot where resstances change most gradually.

Is this because of the old "log approximation" on most log pots?; that is, the 2 linear sections of response rather than a "true logarithmic" response?

Mar 8, 2009 3:42:06 GMT -5 JohnH said:

The blending would be max with an anticlockwise turn.

Is that because I've drawn the thing back-to-front (CCW at the wrong end)? The intuitive behaviour (to ME, anyway) would be that with the pot on "1" (fully CCW), there would only be the selected pups in the output and when the pot is on "10" (fully CW), the level of the "other" pup would be greatest at the output.

Mar 8, 2009 3:42:06 GMT -5 JohnH said:

For parallel blending like this, I find that it mostly happens between 0k and about 30-50k.

How would it be different for series connections? Referring to my thought above, does that mean the 0k->50k range is the "1st slope" on the "log approximations" response? If so, why don't we just use a 50k linear pot? (Heh... the same ol' arguments keep comin' up...)

I'm almost of a mind to do the re-wiring with long fly leads that I can squeeze out under the pickguard and try some different pots wired-in and see how they work...

The puzzle continues...

[JohnH]

I like the last diagram best, and a 250k log pot wired as I noted is my guess at the best value for it.

[ChrisK]

With my suggested design, the "other pup" is actually shorted to ground, so we won't have that "floating return" problem.

With the (signal) returns of all three pickups already connected to signal ground, there can be no floating returns anyway.

When you get to doing series blending (elevating pickups), you could have this issue.

Having one end of the blend pot grounded will effect a volume control for the blended-in pickup not unlike a LP with one pickup set at maximum volume and the other's volume being adjusted. It will allow for the blended pickup to be completely removed from effect.

However, you will now have two 250K pots to ground which will make things less bright.


A series blender will not entirely remove the blended pickup from having effect, but it may well be reduced enough that no one hears of cares. This depends on the value of the pot.

And yes, most log pots are two generally linear slopes joined about the middle of the rotation.

Which one, the original concept I posted OR my take on pete12345's blender posting?

Have it both ways; if you want the clockwise effect of blending in (which only makes sense), use a pan pot (which actually is not a blend pot) and use the left-hand tapered element for series blending (you would use the right-hand element for a "normal" volume blending effect).

And of course, that lever thingy on the bridge of most Strats is not a tremolo, it's a vibrato (or a tremo'Leo).

P.S. I still think that you should keep the left-handed schematic for those that firmly believe that power flows into the guitar from the amp (thru the guitar's input jack).

[ozboomer]

Many thanks for the postings... they're helping me to decide where I'll take this project...

Still, near as I can work out, I don't think it's going to be possible to get the latest diagram above to work with series blending WITHOUT having to resort to something like a 3-way switch; that is, to select between:

• series: blend in neck
  
• parallel
  
• series: blend in bridge
  

Have a look at this:

What we have here is a simplified arrangement of the most recent circuit with the blend pot "splitting" between the neck and bridge pups. To be able to get the series connections between the neck and bridge pups, I'd have to make incompatible connections, for example to have a pup's input connected to ground AND to the input of the "other" pup at the same time.

The only way I can see around that is to have the connections switched, which would mean we'd have to have another switch to select between "blend-in the neck" and "blend-in the bridge". Even if we used the "free" section of the 5-way, that would only take care of, say, the ground switching into one of the pup inputs... Grrrr... This is getting way too hard...

Mar 8, 2009 17:11:24 GMT -5 ChrisK said:

Have it both ways; if you want the clockwise effect of blending in (which only makes sense), use a pan pot (which actually is not a blend pot) and use the left-hand tapered element for series blending (you would use the right-hand element for a "normal" volume blending effect).

Well, y'see, that's getting along the complicated path again... I like the idea of something simple that I can explain easily, hence why I went to the "minimal wire movement" idea. Seeing the option of series blending is looking too hard at the moment (unless someone has a "Eureka!" moment), I'm thinking I'll just stick with the parallel blending option...

...although, I DO like some of the sounds I can get from the series connections in the SPlender mod...

Hmm...

Maybe I'll use this project to determine how important the blending in/out (in parallel) of BOTH the neck and bridge pups is... I might even simplify the SPlender mod and remove the "2-way" blender and just make it so it only ever winds-in the neck (or bridge) pup...

Still, I'll keep making myself crazy for a bit.. and try to make the series option available in this current design...

[xeroks]

to go back to something Pete said about the standard strat set up:

the tone controls are coupled in the N+M position

I've got a Burns Marqee - it's a strat copy. As far as I can tell, one tone controls acts on the neck, the other on the middle coil.

I bumped into a sound on it the other day - N + M, with the neck tone full up and the middle tone full down. It's a kind of hollow sound, reminds me a bit of out-of-phase. Sounds best with a bit (or a lot!) of overdrive.

Is this different from the way a standard strat works? I know there are some differences - it has a push/pull to switch the neck on and off, giving B+N and B+M+N options.

xeroks

[newey]

Xeroks-

A bit of a hijack of this thread, but not completely off topic. So, no worries.

The "Classic" Strat wiring had the tone pots as you describe. They also shared the capacitor between the 2 pots, since the original Start just had a 3-way switch, with only one pickup able to be selected at a time. The shared cap, and the interaction between the tone controls, began when people started filing "notches" in the 3 way switches to get the shorted positions ("2" and "4"), making the 3 way into a 5 way.

Your Burns may, or may not, have a shared tone cap, so I don't know if the wiring is truly identical to the Strat.

[JohnH]

Hey Oz - to help think about your Mk2 design:

What sounds are you liking best from your previous mod? and are there some where you find the in-between blended sounds to be valuable, as against fully switched combinations or those with te blender fully one way?

Ive had two mods with 3sc's and blenders. Personally, I never found any part blended settings in the paralle mode to be better than the fully switched combos. The only interesting blended settings that I have found are series, with bridge and a small amount of neck. Blending though an out of phase range is also fun, but thinking back over a couple of years, I have never actually used it to play a song. That might be to do with my amp set up, which is quite bright. Series with cap bypass on the neck, that is really useful, with N+M or N+ B.

[ozboomer]

Mar 9, 2009 15:06:21 GMT -5 JohnH said:

Hey Oz - to help think about your Mk2 design:

You raise a couple of very good points, JohnH.. and I'm guessing I really should've thought about those things a bit more before I started this project ...

..and now that you mention it, when I play that SPlender mod guitar, I think I do have the "mode" switch sitting in "series" more often than not(!)... hmm...

I'll have a bit of a play about with a more critical ear and see what I'm actually using from the SPlender mod... and this current project may end-up taking a different path..

Oh... and I'll have to see about that cap. bypass option; I need to find some references on how... where... why... about that..

Fanx! for the thoughts... and I'm off to bend my ears some more...


John

[JohnH]

Mar 9, 2009 18:11:56 GMT -5 ozboomer said:

Oh... and I'll have to see about that cap. bypass option; I need to find some references on how... where... why... about that..

You have everything you need to try this already wired into your spendour mod!

On this diagram....



Add one wire from the disconnected end of the tone pot, to the dot at the left end of the middle pup (ie the switch pole that is connected there)

In parallel mode, it does nothing, but in series mode, at full treble, it bypasses the highs from the neck and lets more highs through from the B and M, also lowering the impedance of the guitar at high frequency, and makes an intersting mid notch. Its all very natural to use, at the treble end of the tone pot, you get more treble. Turn the tone down a bit and it reverts to a standard sound. Parallel mode is unaffected.

By the way - I really like this tone control circuit!

John

[ozboomer]

Mar 10, 2009 14:28:40 GMT -5 JohnH said:

You have everything you need to try this already wired into your spendour mod!

Okie... I've made the addition to the diagram, viz:

...but I'll have to wait a while before I can try it out on the guitar (yes, my $ state is that bad at the moment that I can't cope with 'wasting' a set of strings just to try this variation!). Once I try it out, I'll probably put the variation into the "SPlender design" thread.

I'll be keen to hear what difference it makes in the sound... Fanx! JohnH..

Mar 10, 2009 14:28:40 GMT -5 JohnH said:

By the way - I really like this tone control circuit!

D'you mean the modified one OR the 'standard' SPlender -style tone control?

Further thoughts on the current arrangement...

I think I said this in the earlier days of the SPlender mod... but now that I've actually used it for a while, I would agree with what I've read from a few people now, in that the "blend" function on parallel pup connections doesn't really seem to offer much compared to just a simple switching of the pups in and out of the circuit. So, in my list of mods for my "ultimate guitar", I might include a switch to simply switch in/out the non-selected pup in parallel mode -- this would then give the N+M+B and N+B combinations.

I'm still trying to suss-out a simple "series only" blend option... maybe I'll have to do something like I did on the SPlender mod and say only the Neck pup can go in series with the others... but if I have to make a choice like that, I'll probably blend in the bridge, as I have a design that already series-blends the neck pup... and I should probably hear the differences with blending-in the bridge pup.

More bashing the drawing board for me...


John

[ozboomer]

I've been thinking about how I might achieve a series connection between the pups... and still be able to blend one of the pups in/out of the sound in a series mode. So far, I've come up with the following options:

1. Is the simplest and most obvious series connection... but there's no blending on that; a switch between the pups would simply turn a pup off and on.

2. This option provides some sort of blending... but is each pup 'grounded' properly? ...and will the neck pup signal be wound in and out Ok?

3. This seems to be overly redundant somehow (my electronics deserts me again!)...

4. This is the way the blending is done in series mode in the SPlender mod.

...and ya, I realize there will probably still be -some- neck signal in all of these, even when the pot is wound right back because I'm not using a "no load" pot... but I'm not worrying about that right now.

So, what's good/bad about these options? ...or do you have any other suggestions? ...and which is the simplest version to guarantee I can blend a 2nd pup in and out with a 'primary' pup? Should I really be looking at the 3 pups all at the one time when I'm working out the series/blending options?

Appreciate your thoughts, folks...


John

Edit: Modified image to strike the 'tone mod' - Only want to think about true blending options here.

[JohnH]

Oz - Short answer (just going out)

Strike no 2 - doesnt actually blend, just stuffs up the tone of both pups together.

The others are all good, depending whether you want no blending, blending just the neck in and out, or full blending between the two. As you probably know, I like no 4 when Ive blended in my builds.

John

[ozboomer]

After a lot of hours thinking... doing nothing... doing other things... revisiting... etc today, I've come up with this basic (and admittedly ugly) sort of 'series-only' design. I would need to find a 3PDT toggle switch but I think that's Ok... and instead of blending the 'selected' pup with the 'non-selected' pup, this layout will allow me to blend-in the 'selected' pup with the middle pup in series... I think(!):

The only(?) questionable part of the layout is that the pot shown will only act as another volume control and will only allow the middle pup signal through in the '3' position on the 5-way... and positions '1' and '2' are the same (blend neck in with middle) and positions '4' and '5' are the same (blend bridge in with middle)... So, I effectively only add 2 extra (variable) sounds for all the work required, so maybe that's hardly worth doing... maybe. ...but overall, I don't think this is too big a deal, considering I'm really only looking to get the M~xN and M~xB sounds anyway ( heh... my own new notation for a variable series connection )

I realize my 'simplicity' goal is out the window with this... but I don't know if it's even possible to create a variable, series-type connection 'simply'...!

Anyway, thoughts, comments, etc very welcome... Fanx!


John

[ozboomer]

Assuming the series diagram I've posted here almost a week ago is workable, I've come up with the complete circuit for one version of an "X-Blender", viz:

For an "un-split" version of the circuit: link

For this arrangement, I think we will have these switching combinations:

Pa/Se	(N+B) Sw	5-Way	Pups ON
P	Off	N	N
P	Off	N+M	N+M
P	Off	M	M
P	Off	M+B	M+B
P	Off	B	B
P	On	N	N+B
P	On	N+M	N+M+B
P	On	M	N+M+B
P	On	M+B	N+M+B
P	On	B	N+B
S	Off	N	Mx~N
S	Off	N+M	Mx~N
S	Off	M	M
S	Off	M+B	Mx~B
S	Off	B	Mx~B
S	On	N	(Mx~N)+N+B
S	On	N+M	(Mx~N)+N+B
S	On	M	M+N+B
S	On	M+B	(Mx~B)+B+N
S	On	B	(Mx~B)+B+N

...where something like "~N" means a varying amount mixed-into the sound via a pot... and "+" is a parallel connection... and "x" is a series connection.

I see this working like this, somehow:

• With the mode switch set to "parallel" (normal, default) and the "(N+B)" set to "Off", we have the standard sounds
  
  
• With the mode switch set to "parallel" and the "(N+B)" switch set to "On", we have the "(N+B)" Telecaster-type sound and the "all pickups on" sound.
  
  
• With the mode switch set to "series" and the "(N+B)" set to "Off", we have variations based on the M pickup with either the N or the B pickup "blended-in" in series with the M pickup.
  
  
• The combination where the mode switch is set to "series" and the "(N+B)" is set to "On" is not something I was actively looking for...but who knows what it might sound like!?

Any thoughts on this arrangement, then??

Ta...


John

[JohnH]

Interesting!

Some days are not good days for thinking about wiring diagrams, and for me the last week has been seven of them - which is why I didnt get to comment on your last draft.

Lots of sounds. My only comment is that in series mode at mid blend, all the signal goes through the resistance of the blender. To keeo the tone clear, I'd suggest adding a treble bleed cap and resistor from blender top lug to centre lug as drawn. I havent done that on a SSS guitar, but I do use it for series combinations on HH designs, so I know it works OK.

John

[ozboomer]

Mar 21, 2009 0:28:21 GMT -5 JohnH said:

Interesting!

Some days are not good days for thinking about wiring diagrams, and for me the last week has been seven of them - which is why I didnt get to comment on your last draft.

Well, I hope it's interesting enough for a few people to try it out!...

...and a crook week for you, eh? Sorry t'learn that. I think we all know what it's like, though. In my case, it's more like the "good" days are the rare ones(!)

[...]

I've put a cap/resistor across the blender, as you suggested, viz:

...and I'm guessing we can use the same sort of component values for this one (150k/0.001uF)?

Fanx! again for your thoughts...


John

[ozboomer]

To help make my life easier (I think!), I've recently lashed-out on a budget loaded pickguard, viz:

Heh... I'm NOT showing a "front view" until I have it installed in the guitar - gotta have SOME sense of surprise with these things sometimes

For the last few days, I've been trying to suss-out how everything's wired... and it's sort-of been sending me 'round the twist... but I eventually got over that...

One of the immediate questions has been to determine the way the pickups are arranged. To test things out, I'll rest a screwdriver along the poles of the bridge pup. If I then use my analog meter and put the cold probe to the cold wire of the pup and the hot probe to the hot wire of the bridge pup, when I quickly remove the screwdriver, I'll see a positive deflection on the meter.

If I do the same thing on the middle and neck pups, they all cause a positive deflection on the meter... The complication is that if I check the polarity of the magnets on the bottom of the pups, the middle one has a reversed polarity. Now, what does this mean in terms of reverse-wound and the noise-cancelling characteristics of these pickups? Do I wire things so that I get a reverse deflection on the meter for the middle pickup... or because the magnet is "backwards", does that mean I just won't get the hum cancelling?

Anyway, whilst I've been working on how the pickups work, I've been building one of my wiring diagrams for the latest version of the circuit, viz:

image link - this is a 1024-wide image so I decided to not load it up by default.

NOTE: I might have changed the numbering system for the caps/resistors so go by the circuit diagram directly, rather than the component labels if you *do* check-out the wiring.

For some reason, it was quite a battle to get this diagram organized... and it's sort-of turned out to be a not-so-simple re-wiring... but I'd appreciate any thoughts on this or if you find any errors.

One thing ... C2 (in the wiring diagram) is a tone cap. that theoretically goes to ground. Now, if there is any sort of foil on the back of the pickguard, the shells of the pots will all be joined... So, what can I do with that "floating" cap, as it's shown in the wiring diagram? Is it going to be Ok to do the normal thing and run it between the wiper tag of VR2 and onto the pot shell? See the dotted green line in the diagram.

Again, Fanx! for any forthcoming info/thoughts.


John

[newey]

OzB-

One of the immediate questions has been to determine the way the pickups are arranged. To test things out, I'll rest a screwdriver along the poles of the bridge pup. If I then use my analog meter and put the cold probe to the cold wire of the pup and the hot probe to the hot wire of the bridge pup, when I quickly remove the screwdriver, I'll see a positive deflection on the meter.

Why did you/do you feel the need to do this? It's a prewired replacement Strat pickguard, and the pickups are wired (and arranged) as they all are. Unless it's of the "vintage" variety, the middle pup will be RWRP, to give humcancelling in positions 2 and 4.

If I do the same thing on the middle and neck pups, they all cause a positive deflection on the meter... The complication is that if I check the polarity of the magnets on the bottom of the pups, the middle one has a reversed polarity. Now, what does this mean in terms of reverse-wound and the noise-cancelling characteristics of these pickups? Do I wire things so that I get a reverse deflection on the meter for the middle pickup... or because the magnet is "backwards", does that mean I just won't get the hum cancelling?

No, the fact that the magnet is of opposite polarity, coupled with the reverse winding, is what gives you the hum-cancelling. The positive reading on the screwdriver test for both the neck and mid is as would be expected. This means that the two pickups are in phase with each other.

Without going into a long-winded explanation, just think of it that the product of two negatives gives a positive. Because the mid pup is both reverse wound and of opposite magnetic polarity, you get a positive reading on the screwdriver test.

If you either switch the magnet so that it has the same polarity as the neck, or if you swap the wires around, you would then get an opposite reading on the screwdriver test, and your pickups would be out of phase with one another. If you did both operations, then you've done a full 360° and the mid is then identical to the neck (and not hum-cancelling)

I haven't looked at your diagram yet, but I hope the above helps.

[ChrisK]

No, the fact that the magnet is of opposite polarity, coupled with the reverse winding, is what gives you the hum-canceling.

A minor point in that hum cancellation comes solely from the windings being out of phase (winding direction) with each other.

Having the magnets also reversed (of opposite polarity with each other) prevents signal cancellation as well.

[ozboomer]

Apr 17, 2009 21:14:25 GMT -5 newey said:

Why did you/do you feel the need to do this? It's a prewired replacement Strat pickguard, and the pickups are wired (and arranged) as they all are.

Well, I didn't really want to have to install the loaded pickguard into a guitar just to check how the pickups are wound/wired; I thought it would be a useful thing to know how to do, much like the way ChrisK described reading pickup resistances through the jack.

I will be re-wiring this pickguard for the 'X-Blender', y'see... and I just wanted to make sure I re-wired the pickups the right way 'round the first time, so that I get that hum-cancelling happening.