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so... how to have two seymour humbuckers with options to get inside vs outside w hum cancelling like prs...


mistermikev
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hoped someon might find this interesting/useful

inside vs outside coils like a prs... but from seymour duncan pickups...

with semour - the neck bucker is wired exactly the same: fwd wind, fwd polarity (relative) as the bridge.  the physical wires for the neck come out on the opposite side -ie the pickup is flipped- so you get screw coils on the outside. 

so given the pair is wired exactly the sm... when you split both humbuckers (using typical red+white to ground) you'll get both outside coils active... but we don't get hum cancellation.

one way to get around this is to take either pickup and physically flip the magnet, then to wire the pickup exactly reverse to the other.  ie one goes live->black->white->red->green->ground while the other goes live->green->red->white->black->ground.

this wireup takes advantage of that modification such that in (down) normal position on the push pull... you get normal lp operation.  pull up and you get outside coils in the bridge position, and inside coils in the neck position.  Sort of gives you a "tele in combined mode" in the bridge vs a "strat position 2" in the neck.  IMO - much more useful single coils sounds that both feature hum cancelling.

2Humbucker_2P2T_2Vol_3wayTog_v1.3.thumb.png.53d6d5956792003c5d608ad8d130c0af.png

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3 hours ago, mistermikev said:

one way to get around this is to take either pickup and physically flip the magnet,

Or if you have enough slack on the pickup cable, can live with one Seymour Duncan logo appearing upside down and the slug/screw polepieces appearing in the same order as the bridge pickup, just spin the neck pickup around 180 degrees. Admittedly that probably only works best if you have a pickup that looks the same if oriented either way up, such as a Dimarzio with hex polepieces and the same colour bobbins.

Another alternative is to swap the connection order of the two coils in the wiring. There's no reason why the start winding of a coil on either north or south has to be the one that feeds the 'hot' wire of the circuit in order for a humbucker to buck the hum. Using SD wiring colours, Black (hot) -> White -> Red -> Green (ground) will work the same as Red (hot) -> Green -> Black -> White (ground), but will reverse the phase of the whole pickup by 180 degrees and allow you to tap the opposite magnetic polarity coil if you want without rotating the pickup or magnet, Again, the limitation here is that if you want two humbuckers to sound a certain way when combined (say the neck+bridge position on an LP) it won't work, but it can be useful if you're trying to split a humbucker in combination with a middle single coil for that inbetween Strat-type sound, and the middle single isn't reverse wind/reverse polarity relative to the humbucker coil you're trying to split with.

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4 hours ago, curtisa said:

Or if you have enough slack on the pickup cable, can live with one Seymour Duncan logo appearing upside down and the slug/screw polepieces appearing in the same order as the bridge pickup, just spin the neck pickup around 180 degrees. Admittedly that probably only works best if you have a pickup that looks the same if oriented either way up, such as a Dimarzio with hex polepieces and the same colour bobbins.

Another alternative is to swap the connection order of the two coils in the wiring. There's no reason why the start winding of a coil on either north or south has to be the one that feeds the 'hot' wire of the circuit in order for a humbucker to buck the hum. Using SD wiring colours, Black (hot) -> White -> Red -> Green (ground) will work the same as Red (hot) -> Green -> Black -> White (ground), but will reverse the phase of the whole pickup by 180 degrees and allow you to tap the opposite magnetic polarity coil if you want without rotating the pickup or magnet, Again, the limitation here is that if you want two humbuckers to sound a certain way when combined (say the neck+bridge position on an LP) it won't work, but it can be useful if you're trying to split a humbucker in combination with a middle single coil for that inbetween Strat-type sound, and the middle single isn't reverse wind/reverse polarity relative to the humbucker coil you're trying to split with.

thank you for the reply sir and the thoughts. I appreciate the challenge because honestly this is something that has made my head spin for a while and mulling over it only firms up my understanding so thanks for that.

I'm not sure either of those options accomplishes what I was setting out to accomplish... but perhaps that's due to a lack of my defining that.  the goal is to be able to run both screw coils at the sm time, or both slug coils at the sm time... and get hum cancellation.  the additional constraint is that it needs to be inside coils vs outside coils ie a larger vs smaller spread between coils. 

so... if we just flip the pickup... and try to run both screw coils at sm time... we'll have two fwd wound fwd polarity singles screw coils (using fwfp as the arbitrary word to describe the first coils).  in the opposite position we'd get to rwrp slug coils.  additionally, if we flip the neck pickup (for instance) the two screw coils won't be "outside" but rather it would go screw, slug, screw slug... so we'd get less seperation ie 1/3 vs 2/4 coils and we wouldn't get hum cancellation as we haven't flipped polarity AND winding.  

in the second option... we are changing coil order only.  this would be a good option if we were trying to use the middle to wires to ground and give us a split humbucker + hum cancellation... but when we split that way we get one screw coil and one slug coil...and again you wouldn't get outside vs inside.  also might be the right option (as you mention) in a hsh config.  This is also pretty much exactly what I'm doing in my typical rotary wireup with stacked coils.  red -> gree for instance is still the sm winding direction.

I think this may or may not present an achilles heal to the idea I'm presenting above... which is... if you've got the neck two coils in series... but both neck singles have had winding AND polarity flipped... what happens in the typical lp middle position with the two sets of two coils in series?  On the one hand... the bridge 2 will hum cancel on it's own, and the neck 2 will hum cancel on their own... but combining all 4 may have some sort of phase/polarity artifact or at least I seem to recall this happening on some other winding/polarity safari!

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11 hours ago, mistermikev said:

the goal is to be able to run both screw coils at the sm time, or both slug coils at the sm time... and get hum cancellation.  the additional constraint is that it needs to be inside coils vs outside coils ie a larger vs smaller spread between coils. 

Admittedly there's caveats and trade-offs to any suggestions. My first idea is effectively the same as your option of flipping the magnet in the pickup, but carries the proviso that you need to live with the look of the pickup being upside down. It does, however, save you dismantling the pickup to get to the magnet which may be off-putting to some people. If you're not adept and aware of the inner workings of pickup disassembly/reassembly there's every chance you might write off a perfectly decent Seymour Duncan humbucker in the process. 

The second option should also work, but introduces other phasing issues in certain pickup combinations. Indeed, I had to use it recently on an HSS-equipped guitar, where the split-bridge pickup sound when combined with the middle single gave humbucking performance but not the typical Strat-position-2 'quack' sound I was after. Reversing the coil order and tapping the opposite coil on the humbucker fixed the issue without having to worry about flipping magnets or rotating the pickup around. But as you note, it could have unusual tonal effects on an HH guitar if you also want to retain the 'normal' bridge-bridge/neck-neck humbucker switching pattern in addition to the humbucking inner/outer coil tap positions.

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27 minutes ago, curtisa said:

Admittedly there's caveats and trade-offs to any suggestions. My first idea is effectively the same as your option of flipping the magnet in the pickup, but carries the proviso that you need to live with the look of the pickup being upside down. It does, however, save you dismantling the pickup to get to the magnet which may be off-putting to some people. If you're not adept and aware of the inner workings of pickup disassembly/reassembly there's every chance you might write off a perfectly decent Seymour Duncan humbucker in the process. 

The second option should also work, but introduces other phasing issues in certain pickup combinations. Indeed, I had to use it recently on an HSS-equipped guitar, where the split-bridge pickup sound when combined with the middle single gave humbucking performance but not the typical Strat-position-2 'quack' sound I was after. Reversing the coil order and tapping the opposite coil on the humbucker fixed the issue without having to worry about flipping magnets or rotating the pickup around. But as you note, it could have unusual tonal effects on an HH guitar if you also want to retain the 'normal' bridge-bridge/neck-neck humbucker switching pattern in addition to the humbucking inner/outer coil tap positions.

funny thing - I have ruined a few pickups trying to change from 2 conductor to 4... but have flipped/changed mags quite a few times w no issue -but I hear ya - any time you mess with pickup wire there is probably a 40%+ chance of disaster in even experienced hands.  

 

Option1: instead of flipping neck pickup could just use two bridge pickups, which I've done... you can get inside vs outside but don't get slugs vs screws and on a les paul with covers this just doesn't look right IMO. 

Option2: With just normal seymour set you can get the right look but you'll get 1/3 vs 2/4 and no screws vs slugs. 

 

Option3: this way -which is not only a hair sketchy and potentially will not sound as 'big' in the middle position... but if someone ever tries to replace that pickup w something else it would be some mental gymnastics (including myself 2 years down the road!).  On the bright side it should have the biggest tonal variation as the pickup separation is there and some say there are minor audible differences between slugs/screws... and it does "look right".  

so as always... pluses and minus's... so just another option.  

thank you again... at the least the exercise has cemented phase/polarity a bit more in my mind.

 

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From my experience PRS pickups don't feature inside vs outside coil splitting, pretty sure it's just both slug coils in pos 2, certainly isn't hum cancelling. Most of them are 3 conductor so all you can do is ground the screw coil. And from what I understand about their newer fancier "TCI" pickups and the older 408s , it's still a 3 conductor pickup with 4th wire being a tap so the slug coil is tapped in humbucking mode and not tapped when the screw coil is grounded, making it a phatter single coil. On my Pauls Guitar with the 408s, the split coil was actually pretty damn noisy. So the TCI part of it is just resisters for tuned coil splits to reduce hum a bit. 

That is just my interpretation so I might be totally wrong, in which case, tell me to bore off.

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2 minutes ago, ADFinlayson said:

From my experience PRS pickups don't feature inside vs outside coil splitting, pretty sure it's just both slug coils in pos 2, certainly isn't hum cancelling. Most of them are 3 conductor so all you can do is ground the screw coil. And from what I understand about their newer fancier "TCI" pickups and the older 408s , it's still a 3 conductor pickup with 4th wire being a tap so the slug coil is tapped in humbucking mode and not tapped when the screw coil is grounded, making it a phatter single coil. On my Pauls Guitar with the 408s, the split coil was actually pretty damn noisy. So the TCI part of it is just resisters for tuned coil splits to reduce hum a bit. 

That is just my interpretation so I might be totally wrong, in which case, tell me to bore off.

i can't speak to what they do nowadays... but back in the day when the rotary switch was much more common they def did inside vs outside and it was def hum cancelling. 

below is a nice summary of dif schemes through the years.  

-------------------------------------------------------------------

V2 wiring from a mid 1988 Sig
10 – 9.69 (treble)
9 – 13.52 ( MODIFIED power out of phase, just one coil of bass against both coils of treble)
8 – 8.83 (2 coils in series)
7 – 2.30 (strat sound)
6 – 7.99 (bass)

 

’85 to mid ’87

10 – treble PU
9 – both pickups together out of phase aka ‘power out of phase’ (NB the early wiring is different to the later power out of phase wiring)
8 – both pickups in parallel, in phase
7 – inner (slug) coils of both humbucker pickups in parallel
6 – bass PU


Mid ’87 to circa mid ’89

As above except

9 – both pickups out of phase BUT one coil of the neck pickup out of phase against BOTH coils of the treble pickup (my experience is this is a much hasher sound than the original out of phase wiring)
8 – inner (slug) coils of both humbucker pickups in series (replaces previous both pickups in parallel, in phase, wiring)

Post circa mid ‘89

This version is the same as the mid ’87 to circa mid ’89 wiring , EXCEPT position 9 power-out-of-phase changes. However I’ve not owned a guitar with this wiring, so I’m not 100% sure what power out of phase changes to.

 

-----------------------------------------------------------------------------------

here is a diagram showing...

b5a599d725eefc490baeed46e2c3ed34.png

 

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also... afa all you can do is ground - if you look at above drawing it's showing three conductor setup and yes... grounding both series links from screw coils gives you outter coils in parallel.  one could have added positions to send the series link to the other pickups live link and this in fact would give you outter coils in series so it is possible.

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ah, this was the one I was looking for... the prs 513 wiring.  I've kind of always given prs the credit for coming up with the idea of inside vs outside coils... there may have been folks who came up with it earlier but they certainly made it popular.  I remember working at a music shop the first time I saw this wiring... some issues w a guitar and boss asked me if i could fix it (I could not!).  was intimidated as all get out by the complexity of the rotary.  

anywho, my goal was not nec to copy this diagram... but to improve upon it.  basically you get many of these same combos but they are on the 3-way so in theory it overcomes the thing folks hated about this wiring: that it was hard to see where you are and get back to a simple bridge or neck sound.

prs-513-wiring-diagram-2.gif

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Yes, I can confirm that the older 5-way rotary switching scheme is fully humbucking in all positions, but I'd have to open mine up to verify how it's done and what wire colour goes where. There's probably someone out there that's already done the hard work on reverse engineering the wiring on the older CU22 and 24 rotary-switched scheme.

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27 minutes ago, curtisa said:

Yes, I can confirm that the older 5-way rotary switching scheme is fully humbucking in all positions, but I'd have to open mine up to verify how it's done and what wire colour goes where. There's probably someone out there that's already done the hard work on reverse engineering the wiring on the older CU22 and 24 rotary-switched scheme.

right on - thank you very much for confirmation. 

if it's(yours) eighties... perhaps one of these (below) - most do at least one inside coils combo ("parallel single coil" and/or "series single coil").

Idk if prs has changed how they wire their pickups... but as I understand throughout the 80s/90s the whole deal was that their neck pickup was wired different and that def caused some confusion amongst folks trying to work on them or replace pickups.  I believe that would have meant reverse polarity reverse wind relative to the bridge pickup as that's the only way you are going to get screw coils on the outside and ability to do inside vs outside coils w hum cancellation.  of course these were all 3 conductor wiring schemes.

I have a number of sets of older seymour two conductor pickups and dredging this all up has me really thinking about trying to open them up and run a whire from that series link... but that'd def be a gamblers run!

 

Screenshot20190826at.png

 

edit: has me thinking over here... if i had three conductor pickups... and they had the rev wind rev pol on the neck... just connecting those two series wires together in one position on a push pull would effectively give inside vs outside coils on a three way because the live wouldn't connect to the opposing pickup in either extreme of the 3-way and the grounds would be static.  🤔  edit edit - nah... it'd result in 3 coils on as the grounds are static... hmm...

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9 hours ago, mistermikev said:

ah, this was the one I was looking for... the prs 513 wiring.  I've kind of always given prs the credit for coming up with the idea of inside vs outside coils... there may have been folks who came up with it earlier but they certainly made it popular.  I remember working at a music shop the first time I saw this wiring... some issues w a guitar and boss asked me if i could fix it (I could not!).  was intimidated as all get out by the complexity of the rotary.  

anywho, my goal was not nec to copy this diagram... but to improve upon it.  basically you get many of these same combos but they are on the 3-way so in theory it overcomes the thing folks hated about this wiring: that it was hard to see where you are and get back to a simple bridge or neck sound.

prs-513-wiring-diagram-2.gif

Ah I see what you're getting at. I just assumed you were talking about the wiring on the modern ones with the 5 way blade. I don't really understand how the inside vs outside wiring works on the above diagram but then the 5-way rotary wiring makes no sense to me.

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15 minutes ago, ADFinlayson said:

Ah I see what you're getting at. I just assumed you were talking about the wiring on the modern ones with the 5 way blade. I don't really understand how the inside vs outside wiring works on the above diagram but then the 5-way rotary wiring makes no sense to me.

right on, the blade, or "superswitch" - is really no dif than the rotary.  just a 4 pole 5 throw switch.  could do the sm wiring on either rotary or superswitch.  the modern wiring on that is silly imo.  not a fan of 3 single combos (pos 3 below - hums and not particularly intersting) nor a single coil from humbucker by itself (pos 2 below hums and does not sound at all like magnetic poles).  IDK what the heck they were thinking there but... two each his/her own.  the single advantage to that wiring seems to me to be that the wiring itself is fairly simple.

for reference:

5Ccsl9C.jpg

  

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21 minutes ago, ADFinlayson said:

Interesting, I'm personally not a fan of that wiring either. pos 2 and 4 with just a single split humbucker sound a bit meh.

right on.  better off just having a 3-way toggle at that point imo.  someday when I build a prs style prob do a super switch and slight variation on older style wiring.  Really is the cats meow imo.

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2 minutes ago, mistermikev said:

right on.  better off just having a 3-way toggle at that point imo.  someday when I build a prs style prob do a super switch and slight variation on older style wiring.  Really is the cats meow imo.

pos 2 and 4 on the modern widing .ie.

2. both slugs in parallel 
4. bridge hum and neck slug in parallel 

gives plenty of strat quack without as much volume loss or hum IMO.

I did add a mini toggle on my last build so I could split have just the slugs on the neck or bridge but it only sounded any good under gain once I added a couple of resisters into it. I think I put a 1.5k on the bridge and a 2.2 on the neck, or the other way round possibly. 

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1 hour ago, ADFinlayson said:

Something else I noticed about that diagram, whenever I've attempted to ground the pickups on the switch like that instead of back fo the pot, I've always got massive hum. That might just be down to my lack of knowledge on circuitry but I've never had good results doing that.

well... should be able to ground fine... as ultimately it is ground thru the 'out to vol pot casing'.  i can tell you that this wiring scheme would have a fair amount of hum (in specific positions) even if well grounded tho.

 

1 hour ago, ADFinlayson said:

pos 2 and 4 on the modern widing .ie.

2. both slugs in parallel 
4. bridge hum and neck slug in parallel 

gives plenty of strat quack without as much volume loss or hum IMO.

I did add a mini toggle on my last build so I could split have just the slugs on the neck or bridge but it only sounded any good under gain once I added a couple of resisters into it. I think I put a 1.5k on the bridge and a 2.2 on the neck, or the other way round possibly. 

 

afa both slugs in parallel pos2 - well that is one of the 'good' positions for sure.  inside coils in parallel. 

pos4... might be less hum than a single by itself... but crank some gain thru that and you are going to hear more hum than the typical humbucker... just doesn't even make sense.  might as well give all four coils there or any other balanced option imo.  if it works for ya great.

That said I'm pretty sure I'm not alone in thinking that the old prs wiring was where it's at.  

afa splits... and "just slugs" well... perhaps the pickups were not like the old ones.  if you tried just slugs w the typical seymour set... you'd get two out of phase coils which sounds like a 1920s radio with loads of hum.  

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