Quad-rail pickups: manipulating inductance/sensing windows

[sumitagarwal]

I've gotten very intrigued by the idea of quad-rail pickups (DiMarzio Multibucker, Kent Armstrong Motherbucker, Godin Tetrad, Kramer Quadrails, etc) and the unfulfilled potential in them. Most setups use uncreative wiring schemes and even inappropriate components (Godin wired their 4-coil pickups with 250K pots!!!).

Anyways, my thinking is that on a 2-pickup guitar using quad rails, for a total of 8 (eight!) coils, there's an immense opportunity to manipulate the inductance and string sensing windows via creative wiring.

Quad-rail pickups are essentially two single-coil-sized dual-rail pickups placed adjacent to each other. In fact, the DiMarzio Multibucker was literally a Chopper and Fast Track placed into a humbucker-sized casing.

I know many people would consider this goofily esoteric and an over-engineered mentality, but hey this is GuitarNutz 2, right?

For this thought experiment I vaguely modeled it around information I could find Godin's Tetrad pickups which I suspect to be similar to a pair of Dimarzio Fast Track 1's in the neck and a pair of Fast Track 2's in the bridge. I came up with the following wiring schemes to approximate various iconic pickup schemas in both pickup location and output inductance. Very curious for any thoughts or input people may have. Of course this thought experiment sets aside considerations as to the practicality of the wiring and switching.

Based on antigua Chopper analysis (https://guitarnuts2.proboards.com/thread/8502/dimarzio-chopper-analysis-review) I'm assuming a very high 38% coupling boost for adjacent rails and a 15% coupling boost for adjacent single-coil-sized bobbins.

Here we go:

Strat neck




PAF bridge




Strat neck + middle notch




Strat middle + bridge notch




PAF neck





PAF neck + bridge




Tele middle position

[antigua]

I appreciate that you added in the mutual inductance co-efficient. I'm not sure if it's 100% accurate, being inferred from the Chopper values, but it's better than having no estimation at all.

It is crazy to think about all the possibilities, I'd be tempted to have some sort of patch board or bread board to try various arbitrary combinations. I'd have to figure out what the most usable sound were in order to chooses a particular scheme that ends up only offering a fraction of what is possible. In general, the problem tends to be that so many of the combinations will sound like other combinations. I think in general I'd favor parallel over series. Maybe have eight on-off-on toggles to bring any into parallel with all the others, with phase control for each. A tightly loaded Strat pickguard is the only guitar I can think of that would work as a platform. I wired up a red Strat to work like Brian May's Red Special, that was six switches in the place of a Strat selector switch. 


One thing to consider is that aside from the final inductance, when you have imbalanced impedance between two or more coils, the amount of voltage you get from each coil will depend on whether the impedances are in series or parallel.

If you have one coil that is 2H and another that is 1H, in series, the coil will 2H will contribute more signal, so if the 2H coil is the bridge and the 1H is neck, you will get more "bridge" sound than "neck" in the mix, as would be expected. But in parallel, the opposite happens, the 2H bridge will be made weaker than it otherwise would be. This is because the 1H coil will load down the 2H coil more than the 2H coil will load down the 1H coil. The 1H coil won't necessarily be louder, it will just have a boost relative to the 2H coil. The actual end result still factors in the voltage produced by the coils as voltage sources.

[sumitagarwal]

Feb 25, 2024 1:57:30 GMT -5 antigua said:

I appreciate that you added in the mutual inductance co-efficient. I'm not sure if it's 100% accurate, being inferred from the Chopper values, but it's better than having no estimation at all.

It is crazy to think about all the possibilities, I'd be tempted to have some sort of patch board or bread board to try various arbitrary combinations. I'd have to figure out what the most usable sound were in order to chooses a particular scheme that ends up only offering a fraction of what is possible. In general, the problem tends to be that so many of the combinations will sound like other combinations. I think in general I'd favor parallel over series. Maybe have eight on-off-on toggles to bring any into parallel with all the others, with phase control for each. A tightly loaded Strat pickguard is the only guitar I can think of that would work as a platform. I wired up a red Strat to work like Brian May's Red Special, that was six switches in the place of a Strat selector switch. 


One thing to consider is that aside from the final inductance, when you have imbalanced impedance between two or more coils, the amount of voltage you get from each coil will depend on whether the impedances are in series or parallel.

If you have one coil that is 2H and another that is 1H, in series, the coil will 2H will contribute more signal, so if the 2H coil is the bridge and the 1H is neck, you will get more "bridge" sound than "neck" in the mix, as would be expected. But in parallel, the opposite happens, the 2H bridge will be made weaker than it otherwise would be. This is because the 1H coil will load down the 2H coil more than the 2H coil will load down the 1H coil. The 1H coil won't necessarily be louder, it will just have a boost relative to the 2H coil. The actual end result still factors in the voltage produced by the coils as voltage sources.

It's really just thanks to you that I'm even able to make some wild guesstimates at how this might pan out. The information you've gathered really doesn't appear to exist anywhere else on the internet.

There are definitely seemingly-endless possibilities, and I think the granular control over coil-to-coil and coil-to-12th-harmonic distance interval is a critical tonal parameter that we don't normally have access to (for example, it's the defining difference between the Strat 2 position, Strat 4 position, and Tele middle position, all of which sound very different). I would probably start off with seeing how some of the "classic" positions sound, keep the best of those, test out a "built in boost" bridge pickup wiring, and from there muck around with stranger stuff. Once the best combos were determined then it'd be a process to think through how to rig up the best ones using a Free-way 10-way blade plus 2 push-pulls (for the guitar I'm thinking of. I know the 6-way Free-way offers more switching control).

My original thinking was to use alligator clips to try things out, but a breadboard may be much better. I wonder if it would be practical to cut one to the shape of the cavity plate and tape it to that? If you really wanted to get crazy with it, the breadboard could have a bunch of push-button switches so the guitar could be reconfigured after just taking out two screws.

I've struggled to better understand the relative influence of pickups in parallel versus in series. Is there some kind of formula that could describe the proportional contribution? Regardless, in my spreadsheet mock-ups I've been trying to get the contributing pickup sets around the "right" induction level prior to being combined at the final switch (i.e. for the "Tele middle" mock-up I'm having the neck group at 2.07H and the bridge group at 4.08H prior to the final parallel for 1.37H output).

[antigua]

I think the parallel options are the best, because the higher resonant peaks help ensure you don't lose the interesting harmonics that come from the comb filtering, the "notch positions", but I did the math and if all 8 were in parallel, you'd drop all the way down to .33 millihenries, I don't think you would hear any sound at all. Maybe allowing any combination of the individual pickup's coils in series, but then having the two pickups only combine in parallel, would ensure you can have a lot of coils active and never reach rock bottom inductance. You could do that with eight on-on two-way switches with have all the coils on or off  and in series, and one on-on-on for the two pickup (a regular Gibson style pickup toggle) two choose one or both of the pickups.

1 henry per coil in the neck pickup is pretty low, I'd suggest maybe using two bridge pickups so that every coil is 2.6H, and then mitigate the volume difference by setting the pickup heights differently. The difference of 1H to 2.6H is actually a huge difference for a neck and bridge. Even the JB and Jazz are not that far apart in terms of inductance. 

> My original thinking was to use alligator clips to try things out, but a breadboard may be much better. I wonder if it would be practical to cut one to the shape of the cavity plate and tape it to that? If you really wanted to get crazy with it, the breadboard could have a bunch of push-button switches so the guitar could be reconfigured after just taking out two screws.

For initial experimentation. something like this www.amazon.com/HiLetgo-SYB-170-Breadboard-Colorful-Plates/dp/B071KCZZ4K/ ,  the slots in each row are connected to one another, so you would have two rows per coil, one row for the start and finish of each coil, a total of eight rows, and you could connect them any way you want using the jumper wires www.amazon.com/Elegoo-EL-CP-004-Multicolored-Breadboard-arduino/dp/B01EV70C78/   I would just mount it to the face of the guitar for the time being, nothing that can't be undone, but you might need a whole to get the eight wires from the humbuckers from inside the cavity to the outside. I'd solder the jumpers to the pickup leads and tape them up. Definitely label them somehow to know where all sixteen wires lead to. 

> I've struggled to better understand the relative influence of pickups in parallel versus in series. Is there some kind of formula that could describe the proportional contribution? Regardless, in my spreadsheet mock-ups I've been trying to get the contributing pickup sets around the "right" induction level prior to being combined at the final switch (i.e. for the "Tele middle" mock-up I'm having the neck group at 2.07H and the bridge group at 4.08H prior to the final parallel for 1.37H output).

This kind of thing becomes more intuitive with the experiment when you hear surprising volume drops due to changes in the impedances. The match is complicated by the fact that in a circuit analysis, the voltage sources will be assumed to have a fixed value like a battery or AC generator, but in practice the voltage varies, the neck pickup produces more voltage than the bridge and the pickup height and pole piece type changes the coupling coefficient. It's a good argument for trial and error, but not at the exclusion of circuit analysis. 

[sumitagarwal]

Feb 25, 2024 14:09:03 GMT -5 antigua said:

I think the parallel options are the best, because the higher resonant peaks help ensure you don't lose the interesting harmonics that come from the comb filtering, the "notch positions", but I did the math and if all 8 were in parallel, you'd drop all the way down to .33 millihenries, I don't think you would hear any sound at all. Maybe allowing any combination of the individual pickup's coils in series, but then having the two pickups only combine in parallel, would ensure you can have a lot of coils active and never reach rock bottom inductance. You could do that with eight on-on two-way switches with have all the coils on or off  and in series, and one on-on-on for the two pickup (a regular Gibson style pickup toggle) two choose one or both of the pickups.

1 henry per coil in the neck pickup is pretty low, I'd suggest maybe using two bridge pickups so that every coil is 2.6H, and then mitigate the volume difference by setting the pickup heights differently. The difference of 1H to 2.6H is actually a huge difference for a neck and bridge. Even the JB and Jazz are not that far apart in terms of inductance. 

> My original thinking was to use alligator clips to try things out, but a breadboard may be much better. I wonder if it would be practical to cut one to the shape of the cavity plate and tape it to that? If you really wanted to get crazy with it, the breadboard could have a bunch of push-button switches so the guitar could be reconfigured after just taking out two screws.

For initial experimentation. something like this www.amazon.com/HiLetgo-SYB-170-Breadboard-Colorful-Plates/dp/B071KCZZ4K/ ,  the slots in each row are connected to one another, so you would have two rows per coil, one row for the start and finish of each coil, a total of eight rows, and you could connect them any way you want using the jumper wires www.amazon.com/Elegoo-EL-CP-004-Multicolored-Breadboard-arduino/dp/B01EV70C78/   I would just mount it to the face of the guitar for the time being, nothing that can't be undone, but you might need a whole to get the eight wires from the humbuckers from inside the cavity to the outside. I'd solder the jumpers to the pickup leads and tape them up. Definitely label them somehow to know where all sixteen wires lead to. 

> I've struggled to better understand the relative influence of pickups in parallel versus in series. Is there some kind of formula that could describe the proportional contribution? Regardless, in my spreadsheet mock-ups I've been trying to get the contributing pickup sets around the "right" induction level prior to being combined at the final switch (i.e. for the "Tele middle" mock-up I'm having the neck group at 2.07H and the bridge group at 4.08H prior to the final parallel for 1.37H output).

This kind of thing becomes more intuitive with the experiment when you hear surprising volume drops due to changes in the impedances. The match is complicated by the fact that in a circuit analysis, the voltage sources will be assumed to have a fixed value like a battery or AC generator, but in practice the voltage varies, the neck pickup produces more voltage than the bridge and the pickup height and pole piece type changes the coupling coefficient. It's a good argument for trial and error, but not at the exclusion of circuit analysis. 

Yea, there are three "layers" in which there are opportunities to either go series or parallel, so I suspect some combination of series and parallel will be best for most tones. Will only know by testing!

Thanks for the breadboard links! I think it'll actually be pretty fun.

Now I just need to go ahead and get the pickups. The funny thing is I went down this rabbit hole because of frustration with noise on PRS TCI "S" pickups, and chasing down that issue also lead me to these fiberboard humbucker baseplates that might be ideal for mounting, say, pairs of Strat-sized DiMarzio rail humbuckers: www.mojotone.com/Fiberboard-Humbucker-Frame-50mm_2

On those newer PRS pickups on the SE Paul's Guitar model and SE 24-08 model I've seen a lot of complaints online about noise. I believe what's going on is that Paul Smith (or his team) made an engineering error in trying to convert the USA TCI pickup design to the import line. From what I can tell, the USA TCI pickup has a plastic/fiberboard baseplate to improve the single-coil sound, and when designing the imported TCI "S" version they used an intentionally ungrounded metal baseplate instead. It also appears the earlier years had a nickel baseplate and more recent revisions have brass, which maybe exacerbated the issue?

Anyways I was thinking about buying fiberboard baseplates to see if it helps these PRS pickups and realized they might also be a good mounting solution for Strat-sized pickup pairs in a humbucker route.

[JohnH]

I agree that some kind of temporary patch board or external switching will be good for testing before deciding on permanent wiring. That might add a bit of noise, which would be much improved in a final version.

My guess is that the best sounds will be either one rail pair, with its own coils in series or parallel. Or both pairs, overall in series or parallel and also try series or parallel within each pair.

ie out of all those, all arrangements are symmetrical with 2 or 4 coils and all are hum-cancelling. And out of them, I'm guessing that maybe three or four will be chosen for putting into a permanent switching scheme?

[sumitagarwal]

Feb 25, 2024 15:48:00 GMT -5 JohnH said:

I agree that some kind of temporary patch board or external switching will be good for testing before deciding on permanent wiring. That might add a bit of noise, which would be much improved in a final version.

My guess is that the best sounds will be either one rail pair, with its own coils in series or parallel. Or both pairs, overall in series or parallel and also try series or parallel within each pair.

ie out of all those, all arrangements are symmetrical with 2 or 4 coils and all are hum-cancelling. And out of them, I'm guessing that maybe three or four will be chosen for putting into a permanent switching scheme?

Yes, after testing out combinations the plan is to pick some of the best and see if I can wire them up in an intuitive way with a 5-way blade switch and two push-pulls, or possibly incorporating the Free-way 10-way blade. The switching doesn't need to be simple, but I'd want it to be reasonably intuitive and consistent.

My preference will be towards hum-cancelling configurations, but with so many coils to work with I anticipate that there will be some good sounds that are partially hum-cancelling (i.e. some asymmetric combination of series and parallel coils).

[antigua]

Feb 25, 2024 15:18:56 GMT -5 sumitagarwal said:

Feb 25, 2024 14:09:03 GMT -5 antigua said:

Yea, there are three "layers" in which there are opportunities to either go series or parallel, so I suspect some combination of series and parallel will be best for most tones. Will only know by testing!

Thanks for the breadboard links! I think it'll actually be pretty fun.

Now I just need to go ahead and get the pickups. The funny thing is I went down this rabbit hole because of frustration with noise on PRS TCI "S" pickups, and chasing down that issue also lead me to these fiberboard humbucker baseplates that might be ideal for mounting, say, pairs of Strat-sized DiMarzio rail humbuckers: www.mojotone.com/Fiberboard-Humbucker-Frame-50mm_2

On those newer PRS pickups on the SE Paul's Guitar model and SE 24-08 model I've seen a lot of complaints online about noise. I believe what's going on is that Paul Smith (or his team) made an engineering error in trying to convert the USA TCI pickup design to the import line. From what I can tell, the USA TCI pickup has a plastic/fiberboard baseplate to improve the single-coil sound, and when designing the imported TCI "S" version they used an intentionally ungrounded metal baseplate instead. It also appears the earlier years had a nickel baseplate and more recent revisions have brass, which maybe exacerbated the issue?

Anyways I was thinking about buying fiberboard baseplates to see if it helps these PRS pickups and realized they might also be a good mounting solution for Strat-sized pickup pairs in a humbucker route.

I'm not familiar at all with the PRS pickup situation. An ungrounded conductive metal part will for sure cause noise, as it basically acts as an amplifier of RF if it's not grounded, as it couples with noise sources and become a noise source itself. 


Another thing I notice after trying lots of combos, is that by and large, there are six obvious sounds, and a Strat covers five of them, B, M, N, B+M, B+N, and M+N. I mod most of my Strats to add in B+M+N and B+N, but I've stopped doing that so religiously with some newer Strat I've bought, because I can often use the middle pickup to do the B+N sound that Tele's and Gibsons are known for, and the B+M+N tone is very pretty but not all that much different from the Strat M+N tone. 

I had a guitar equipped with Seymour Duncan P-Rails, and it was good and offering some sounds that other pickups can't, because it had a single rail coil hanging off the end. With the rails on the inside edges, you would get and off-center middle pickup sound, which was also very pretty, especially for finger style work, pseudo acoustic guitar tones, but again I didn't feel like I'd miss them too much because they were still in throwing distance of the Strat middle pickup, or the B+N tone of a two pickup guitar. I think part of the reason I'm close minded about the possibilities is the same reason everyone else is; 98% of popular music was recorded with a Fender guitar, or an HH from Gibson or Gretsch or Rickenbacker, and so I think too much in terms of what is familiar. 

The resonant peak of a pickup combo can have a lot of influence over how it's perceived too though. For example, many when people talk about how a Strat pickup that is 2 henries differ from one that is 3 henries, the  say the 3 henry pickup has a bolder attack, more mids and bass, more compressed sounding... lots of adjectives to just describe a lower frequency shelf. Its a small technical difference but a big psychoacoustic difference that leads to lots of pickups on the market with only a minor spec difference. The same is true for the individual pickup combinations, especially because they're so rich with harmonics, if you trim it at a given frequency, it changes the perceived sound a lot. Where I notice it the most is the Strat middle position, by itself at 2H it sounds sort of thin and wimpy, its a running joke that it doesn't get much love from Strat players,  but you drop the resonant peak (with a cap, or with high inductance, or an EQ pedal) it will sound almost identical to Lindsey Buckingham's Turner Mark I, a thicker middle tone that is upfront in the mix and distorts really nicely. It's a hidden gem that guitarists often don't find. I might not have appreciated it if not for Lindsey B making so much great music with the Mark 1 though. 

[sumitagarwal]

Feb 25, 2024 21:12:16 GMT -5 antigua said:

Feb 25, 2024 15:18:56 GMT -5 sumitagarwal said:

Yea, there are three "layers" in which there are opportunities to either go series or parallel, so I suspect some combination of series and parallel will be best for most tones. Will only know by testing!

Thanks for the breadboard links! I think it'll actually be pretty fun.

Now I just need to go ahead and get the pickups. The funny thing is I went down this rabbit hole because of frustration with noise on PRS TCI "S" pickups, and chasing down that issue also lead me to these fiberboard humbucker baseplates that might be ideal for mounting, say, pairs of Strat-sized DiMarzio rail humbuckers: www.mojotone.com/Fiberboard-Humbucker-Frame-50mm_2

On those newer PRS pickups on the SE Paul's Guitar model and SE 24-08 model I've seen a lot of complaints online about noise. I believe what's going on is that Paul Smith (or his team) made an engineering error in trying to convert the USA TCI pickup design to the import line. From what I can tell, the USA TCI pickup has a plastic/fiberboard baseplate to improve the single-coil sound, and when designing the imported TCI "S" version they used an intentionally ungrounded metal baseplate instead. It also appears the earlier years had a nickel baseplate and more recent revisions have brass, which maybe exacerbated the issue?

Anyways I was thinking about buying fiberboard baseplates to see if it helps these PRS pickups and realized they might also be a good mounting solution for Strat-sized pickup pairs in a humbucker route.

I'm not familiar at all with the PRS pickup situation. An ungrounded conductive metal part will for sure cause noise, as it basically acts as an amplifier of RF if it's not grounded, as it couples with noise sources and become a noise source itself. 


Another thing I notice after trying lots of combos, is that by and large, there are six obvious sounds, and a Strat covers five of them, B, M, N, B+M, B+N, and M+N. I mod most of my Strats to add in B+M+N and B+N, but I've stopped doing that so religiously with some newer Strat I've bought, because I can often use the middle pickup to do the B+N sound that Tele's and Gibsons are known for, and the B+M+N tone is very pretty but not all that much different from the Strat M+N tone. 

I had a guitar equipped with Seymour Duncan P-Rails, and it was good and offering some sounds that other pickups can't, because it had a single rail coil hanging off the end. With the rails on the inside edges, you would get and off-center middle pickup sound, which was also very pretty, especially for finger style work, pseudo acoustic guitar tones, but again I didn't feel like I'd miss them too much because they were still in throwing distance of the Strat middle pickup, or the B+N tone of a two pickup guitar. I think part of the reason I'm close minded about the possibilities is the same reason everyone else is; 98% of popular music was recorded with a Fender guitar, or an HH from Gibson or Gretsch or Rickenbacker, and so I think too much in terms of what is familiar. 

The resonant peak of a pickup combo can have a lot of influence over how it's perceived too though. For example, many when people talk about how a Strat pickup that is 2 henries differ from one that is 3 henries, the  say the 3 henry pickup has a bolder attack, more mids and bass, more compressed sounding... lots of adjectives to just describe a lower frequency shelf. Its a small technical difference but a big psychoacoustic difference that leads to lots of pickups on the market with only a minor spec difference. The same is true for the individual pickup combinations, especially because they're so rich with harmonics, if you trim it at a given frequency, it changes the perceived sound a lot. Where I notice it the most is the Strat middle position, by itself at 2H it sounds sort of thin and wimpy, its a running joke that it doesn't get much love from Strat players,  but you drop the resonant peak (with a cap, or with high inductance, or an EQ pedal) it will sound almost identical to Lindsey Buckingham's Turner Mark I, a thicker middle tone that is upfront in the mix and distorts really nicely. It's a hidden gem that guitarists often don't find. I might not have appreciated it if not for Lindsey B making so much great music with the Mark 1 though. 

The PRS TCI "S" thing seems like a weird and very obvious design flaw. As soon as I added grounded washers to the mounting screws the noise went away and, probably because I wasn't getting distracted by the noise, it seemed to me the tone improved as well.

Whether it's due to the conventional 6 tones being so ingrained in our collective memory or simply because there is only so much that can be done within the confines of the fingerboard to the bridge, I agree with you. With apologies to Greeny and Brian May I've always found I hate out-of-phase options. FWIW I usually even find the humbucker + humbucker middle position relatively useless as well unless paired up with independent volume controls to tweak the relationship between the two.

I ran a poll with a few dozen voters each picking up to 5 key sounds, and the ranking was about what you'd expect:
#1 Strat neck
#2 Tied - Tele bridge or PAF bridge
#4 Strat middle + bridge
#5 Strat neck + middle
#6 Tied - PAF neck or PAF neck + bridge
#8 Tele neck + bridge

There was almost no love for the Strat middle pickup solo, which was kind of surprising to me.

When people talk about series combination tones (a lot of folks like a Tele neck + bridge in series) I don't really understand those to be distinct "tones" in the way that I think of them, but more like a way of manipulating the wind and therefor the output/resonant peak/etc (although as you pointed out, series-vs-parallel does affect the balance between the coils).

I was originally interested in the P-Rails but the reviews on them are very mixed. One of the ideas I did like from that, which partially led me down the quad-rail path, is that rail at the end which better approximates the coil interval of Strat notch positions. In particular on a 24-fret guitar I think the quad rails are interesting because you can get a very good notch position spacing, and if using the outermost rail of the neck pickup you scoot just slightly closer to the classic 24th harmonic Strat neck location.

I think it also helps to keep in mind how dynamic the positioning considerations are. For example, we think of a single coil at the 24th harmonic as having the fullest or "sweetest" tone, but in actuality once you play above the 12th fret then a single coil placed where it is on a 24-fret guitar gets closer to the middle of the vibrating length. So it's all dynamic and interacting with the playing.

Added to this, equal lengths of pickup positioning change have a much bigger effect for the bridge pickup than the neck pickup (unless you're playing entirely C# minor pentatonic box jammed up against the 24th fret). For this I think it's useful to think of pickup position and positioning interval in terms of semi-tones away from the middle of the scale length. Viewed that way, quad rails allow precise targeting.

Not to veer to far off topic but I'm curious where your current opinions are on rails vs stacks given your long journey so far. And, completely unrelated, would also be curious about where active and shielded (i.e. Lace) land in the scheme of things for you.

[antigua]

> There was almost no love for the Strat middle pickup solo, which was kind of surprising to me.

I'm not too surprised, it isn't heard a lot in popular music, I don't think. I often use it for a clean rhythm tone that is less bassy and more plucky that that neck, but not as harsh as the bridge. I guess that's a statement of the obvious, but I would say I value its utility more than its tone. 

> When people talk about series combination tones (a lot of folks like a Tele neck + bridge in series) I don't really understand those to be distinct "tones" in the way that I think of them, but more like a way of manipulating the wind and therefor the output/resonant peak/etc (although as you pointed out, series-vs-parallel does affect the balance between the coils).

The tone is fine, my issue is mostly that it's so much louder than the bridge or neck alone. I still think the parallel sound is a prettier sound.

> I think it also helps to keep in mind how dynamic the positioning considerations are. For example, we think of a single coil at the 24th harmonic as having the fullest or "sweetest" tone, but in actuality once you play above the 12th fret then a single coil placed where it is on a 24-fret guitar gets closer to the middle of the vibrating length. So it's all dynamic and interacting with the playing.

That is true, I notice that with my 24 fret guitars, but playing past the 12th fret is almost a special occasion, for most music. 

> Not to veer to far off topic but I'm curious where your current opinions are on rails vs stacks given your long journey so far. And, completely unrelated, would also be curious about where active and shielded (i.e. Lace) land in the scheme of things for you.


I think lower inductance rails are the best, with steel blades - with the full rails in place. The Seymour Duncan Vintage Rails would be cool, but they cut the rails in half, probably for looks, and sabotage the magnetic coupling, which I think was a misguided design choice. I have some very hot rails, the Bill Corgan DiMarzios, with those run in parallel I think you get a really killer Fender-like quiet single coil sound. SD Hot Rails in parallel probably work as well, but I've never bought or tried them out. Amazon sells rails of this sort for as little as $12 so there's no need to buy DiMarzio or Seymour Duncan rails. I would go so far as to say the <$20 rails you get on Amazon are the pinnacle of pickup design, for this reason, and for all their flexibility. These quad buckers are the best thing, times two. I just haven't had the urge to experiment with them yet, mostly because I felt that I retreated to the standard tones when I spent some time with the P-Rails. 

The Seymour Duncan Little 59, Little JB should be killer for the fact that they're like rails, but the screws, which seem to be mostly decorative, lower the magnetic coupling by a lot, making them sound softer than proper rails. They sound decent in split or parallel, but again, a little soft.

On paper, the steel blades should cause eddy currents that soften up the sound more than you'd want with Fender single coils, but with 500k pots the Q factor is retained well, and you get a sharp sound from the narrow aperture, and I think the two steel blades have a strong coupling with the guitar strings, especially if they protrude up out of the pickup, creating a reasonably strong magnetism at the strings. 

The Mojotone Quiet Coils are rails that use AlNiCo bar rails, like a miniature Gibson Firebird pickup. They seem killer in concept, AlNiCo blades instead of AlNiCo pole pieces, but they had a weaker coupling with the guitar strings, and a weaker sound. The AlNiCo blades are not as strong as Fender's AlNiCo pole pieces, and they have a lower permeability than the steel blades, two strikes against them. It's the kind of thing I thought would have worked out well until I tried them and discovered it didn't. Mojotone had fake looking pole pieces in the pickup cover, I think they were on the right track but they didn't look very realistic. Maybe steel blades with a neodymium base magnet would be worth trying instead, that's almost what a Zexcoil is. 

Stacks end up having a mushy sound because the dummy coil is co-axial with the primary coil, and the dummy coil is high impedance. They're kind of a stupid design when you think about it, when you consider that a PAF humbucker uses the same basic parts, but gives you *more* output rather than less. A stacked humbucker is a tacky compromise of a pickup. I tried several but as of now none of my guitars have any installed. 

The Lace Sensors aren't bad, not humbucking, but just single coils with an improved S/N ratio, by having a small coil places very close to the strings, and decent grounded shielding. I think the main reason they don't sound like regular Strat pickups is because they used rubberized ferrite magnets, it's a weaker type of magnet intended to fill odd shapes, but isn't very strong. Companies like Lace try to turn lemons into lemonade by saying it reduces string pull and sound more natural, but guitarists don't want that, they really want are Strat pickups that sounds unnatural and magnetically sucks at the strings, it's "the sound". The rails with steel blades have low magnetism also compared to AlNiCo pole pieces, but to my ears, Lace Sensors sound softer than rails. I think that's a bit of a plus with the Lace Sensor Blue or Red when they're faking a humbucker tone, but a drawback for the Golds, when you want the Fender single coil bite of a stronger magnetic field. 

[ms]

Suppose that you have a 10,000 turn single coil pickup, using steel cores or blade.  Now make a pickup with two 5,000 turn coils in series.  An important difference is that the output levels could be similar, but the inductance of the two coil pickup would be lower.  This is because output level varies roughly with the number of turns while the inductance can vary as quickly as the square of the number of turns.  If so, the inductance of each of the two coils is one quarter of that of the single coil, and the series combination is one half.  Now try four coils.  Output level should stay about the same, but the inductance should drop further.  So it seems to me that a quad rail pickup is a way of keeping the output level high and lowering the inductance.

[antigua]

Feb 27, 2024 6:21:18 GMT -5 ms said:

Suppose that you have a 10,000 turn single coil pickup, using steel cores or blade.  Now make a pickup with two 5,000 turn coils in series.  An important difference is that the output levels could be similar, but the inductance of the two coil pickup would be lower.  This is because output level varies roughly with the number of turns while the inductance can vary as quickly as the square of the number of turns.  If so, the inductance of each of the two coils is one quarter of that of the single coil, and the series combination is one half.  Now try four coils.  Output level should stay about the same, but the inductance should drop further.  So it seems to me that a quad rail pickup is a way of keeping the output level high and lowering the inductance.

Another way of putting it is that it lowers the proportion of parasitic L and C relative to the amount of voltage generated, not unlike spacing out the circuit on a PCB for the same kind of reasons. 

[sumitagarwal]

Feb 27, 2024 6:21:18 GMT -5 ms said:

Suppose that you have a 10,000 turn single coil pickup, using steel cores or blade.  Now make a pickup with two 5,000 turn coils in series.  An important difference is that the output levels could be similar, but the inductance of the two coil pickup would be lower.  This is because output level varies roughly with the number of turns while the inductance can vary as quickly as the square of the number of turns.  If so, the inductance of each of the two coils is one quarter of that of the single coil, and the series combination is one half.  Now try four coils.  Output level should stay about the same, but the inductance should drop further.  So it seems to me that a quad rail pickup is a way of keeping the output level high and lowering the inductance.

Took me a while to understand exactly what you guys were describing, but it makes rails sound pretty advantageous and pushed me over to edge to pull the trigger on this strange bird which I grabbed for$360:

Godin LG 2001 - Natural Walnut - Quad Rail Humbuckers reverb.com/item/78382175?utm_source=android-app&utm_medium=android-share&utm_campaign=listing&utm_content=78382175

[sumitagarwal]

Oh man, I was just looking over the instructions for the Duncan Hyperswitch, which is a Bluetooth programmable 5 way. Between that and two push-pulls might be able to access almost every combination without dealing with a bread board... very interesting times we're in!

[stratotarts]

FYI, quad rails are available on the import market. Based on the dual rails I have looked at, they should be pretty normal, i.e. no big skimping on wind count, very comparable to similar name brand offerings. I had one (dual coil blade HB) in the middle position of an Ibanez RG, it sounded great all by itself. If you're just experimenting you could save some big money there.

I came across those just after the end of the times when I would buy pickups, just to test them. So I never owned any. The Tele has the SuperSwitch for playing around, for other guitars you need something like a rotary wafer switch.

[sumitagarwal]

Well, I got this weird guitar and it's shame that it was so poorly treated earlier and also poorly packed, because it clearly was originally very nicely built. I'm sending it back for a refund because it's beat to hell and arrived with a crack developing in the neck near the nut.

I can't quite tell what the push-pull tone pot is doing. Maybe a phase switch? The 5-way switch seems to be providing splits in positions 2 and 4 such that the selections are:

Neck both pickups
Neck inner pickup
All four pickups
Bridge inner pickup + neck inner pickup? Unsure
Bridge both pickups

Perhaps more interesting is the sort of "factory custom" design where the "2" pickups are literally four separate pickups screwed to the body! Makes the guitar ready-to-go for experimenting with some other Strat-sized pickups, so long as they don't have the vintage-style triangular baseplates.

You can even see that they cut the corners of the pickup baseplates to make them fit! If nothing else I appreciate just how weird this thing is. I also can't tell what kind of finish it has, but it is very thin and satin, not at all like your typical hard thick poly finish. I'm a fan

[sumitagarwal]

I'm thinking about grabbing these solderless push-pull pots as a way to quickly test out different coils and pot values, is anyone familiar with them or have any thoughts?


toneshapers.com/products/cts-pot-500-250k-audio-push-pull-switched-split-shaft?_pos=1&_sid=bc7b56a66&_ss=r

[stevewf]

Mar 17, 2024 11:47:51 GMT -5 sumitagarwal said:

I'm thinking about grabbing these solderless push-pull pots as a way to quickly test out different coils and pot values, is anyone familiar with them or have any thoughts?


toneshapers.com/products/cts-pot-500-250k-audio-push-pull-switched-split-shaft?_pos=1&_sid=bc7b56a66&_ss=r

They offer a single product for "500k/250k (selectable) audio taper" in what looks like a single-gang pot. This would mean that there's a pot-plus-resistor scheme going on, which I've learned by rote here at GN2 is not the same as a "natural" pot. Aside from that and the added cavity space requirement, it looks like it'd work just fine.

[sumitagarwal]

Mar 18, 2024 0:18:33 GMT -5 stevewf said:

Mar 17, 2024 11:47:51 GMT -5 sumitagarwal said:

I'm thinking about grabbing these solderless push-pull pots as a way to quickly test out different coils and pot values, is anyone familiar with them or have any thoughts?


toneshapers.com/products/cts-pot-500-250k-audio-push-pull-switched-split-shaft?_pos=1&_sid=bc7b56a66&_ss=r

They offer a single product for "500k/250k (selectable) audio taper" in what looks like a single-gang pot. This would mean that there's a pot-plus-resistor scheme going on, which I've learned by rote here at GN2 is not the same as a "natural" pot. Aside from that and the added cavity space requirement, it looks like it'd work just fine.

Thank you! I did not know that..