Coil Tapping Question

thegummy

Hopefully one of the very knowledgeable people can answer this:

When a pickup has a coil tap (genuinely meaning a coil tap, not a split) - when it is in the tapped setting, would it act exactly like as if the pickup only had that much wire to begin with?

Or does the fact there's extra wire on there, even if it's disconnected, affect the signal in some way, even if subtly?

I.e. is a coil tap always a compromise or can a hot pickup with a tap give the same sound as a lower output pickup (if it happened to be otherwise made the same)?

Winny_Pooh

Not enough to worry about. More problematic is that a single coil on a humbucker is wound significantly weaker than a Fender single and uses a bar magnet instead. 

Best tapped sound from a humbucker is using a resistor to reduce one coil's output. Some like 3k-5k but I prefer 8k-10k. 

OilCityPickups

I answer this here :-)

CasperCaster

I've had a number of tapped single coil pickups over the years and whilst I haven't had the opportunity to compare tapped versus similarly spec'd non-tapped variants, I would say the best of the breed sound very good, with no obvious sonic compromises.

My only concern has been noise, as the low output tap can sometimes be slightly noisy depending on how the tap is selected ( the additional windings can act as an aerial if the high output is left floating). I prefer to wire both hots together for the low output tap, then lift the low output tap to select the full output. Essentially in the low output setting both ends of the additional windings are at the same potential and are less inclined to add noise  to the output.

ICBM

CasperCaster said:

I prefer to wire both hots together for the low output tap, then lift the low output tap to select the full output. Essentially in the low output setting both ends of the additional windings are at the same potential and are less inclined to add noise  to the output.

It’s always better to switch any tap or split like this, for that reason.

It’s also more reliable since if the switch contact fails you’re left with the full pickup, rather than no connection which you get if you’re selecting one or the other.

thegummy

TheGuitarWeasel said:

I answer this here :-)

Much appreciated!  

thegummy

CasperCaster said:

I've had a number of tapped single coil pickups over the years and whilst I haven't had the opportunity to compare tapped versus similarly spec'd non-tapped variants, I would say the best of the breed sound very good, with no obvious sonic compromises.

My only concern has been noise, as the low output tap can sometimes be slightly noisy depending on how the tap is selected ( the additional windings can act as an aerial if the high output is left floating). I prefer to wire both hots together for the low output tap, then lift the low output tap to select the full output. Essentially in the low output setting both ends of the additional windings are at the same potential and are less inclined to add noise  to the output.

Think I only partially understand this, maybe if I read it again later with a diagram I'll follow.

CasperCaster

Consider how the pickup is made. A tapped single coil pickup typically only has three wires (I believe Jamie at The Creamery does make some 4-wire tapped single coil pickups, such that both sets of windings are entirely discrete, but that's not usual). Anyway, for a typical 3-wire tapped single coil pickup assume earth is the start of the coil. From that point the pickup is wound to give the first output/tap output (for the sake of argument, a 6K vintage output). This vintage output would be the finish of the coil in a normal pickup. In our 3-wire tapped single coil pickup this first 6K output is also the start of the additional windings, so the two sets of windings are always joined at this point. Anyway, from the first output the pickup is then wound on by a further 3K and then terminated again to give the second final hot output (for the sake of argument this is at 9K i.e. 6K + 3K).

So, with the earth side of the pickup soldered to the back of a volume pot, most wiring diagrams will then select between the two outputs with a minimum of a SPDT switch (push/pull, mini toggle or whatever), where the centre terminal is the output from the switch (going in to the rest of the guitars wiring), and where each of the outer terminals is one or other of the hot outputs from the pickup (6K and 9K respectively in this example). The problem here is that when the vintage 6K output is selected the additional windings (the additional 3K which is added to create the hot 9K output) is still connected to the vintage 6K hot output, because the additional 3K windings are not discretely separate (remember the finish of the first winding is also the start for the additional 3K). However, the second 9K hot output is not connected to anything (left floating), and can act as an aerial injecting noise at the vintage 6K output which is the common point for both sets of windings.

A remedy is very simple. Solder the earth to the back of the volume pot as usual. Solder the vintage 6K output to a simple SPST make/break switch then solder the output of the SPST switch together with the 9K hot output and take this on to the rest of your guitar wiring. With the switch open the output will be from the hot 9K output. With the switch closed both hots are tied together, and as such both the start and finish of the extra 3K windings are also tied together, and so do not contribute noise or signal (both ends of 3K windings at same potential, no longer floating, does not act as an aerial). 

thegummy

CasperCaster said:

Consider how the pickup is made. A tapped single coil pickup typically only has three wires (I believe Jamie at The Creamery does make some 4-wire tapped single coil pickups, such that both sets of windings are entirely discrete, but that's not usual). Anyway, for a typical 3-wire tapped single coil pickup assume earth is the start of the coil. From that point the pickup is wound to give the first output/tap output (for the sake of argument, a 6K vintage output). This vintage output would be the finish of the coil in a normal pickup. In our 3-wire tapped single coil pickup this first 6K output is also the start of the additional windings, so the two sets of windings are always joined at this point. Anyway, from the first output the pickup is then wound on by a further 3K and then terminated again to give the second final hot output (for the sake of argument this is at 9K i.e. 6K + 3K).

So, with the earth side of the pickup soldered to the back of a volume pot, most wiring diagrams will then select between the two outputs with a minimum of a SPDT switch (push/pull, mini toggle or whatever), where the centre terminal is the output from the switch (going in to the rest of the guitars wiring), and where each of the outer terminals is one or other of the hot outputs from the pickup (6K and 9K respectively in this example). The problem here is that when the vintage 6K output is selected the additional windings (the additional 3K which is added to create the hot 9K output) is still connected to the vintage 6K hot output, because the additional 3K windings are not discretely separate (remember the finish of the first winding is also the start for the additional 3K). However, the second 9K hot output is not connected to anything (left floating), and can act as an aerial injecting noise at the vintage 6K output which is the common point for both sets of windings.

A remedy is very simple. Solder the earth to the back of the volume pot as usual. Solder the vintage 6K output to a simple SPST make/break switch then solder the output of the SPST switch together with the 9K hot output and take this on to the rest of your guitar wiring. With the switch open the output will be from the hot 9K output. With the switch closed both hots are tied together, and as such both the start and finish of the extra 3K windings are also tied together, and so do not contribute noise or signal (both ends of 3K windings at same potential, no longer floating, does not act as an aerial). 

I really appreciate the explanation, thanks a lot.

My bass with taps is wired the first way you explain (by myself, can't remember what factory was like) so will need to rewire it when I get a chance.

CasperCaster

@thegummy if I was wiring from scratch I would do it by my preferred method as I think it's the best way to do it, but the other way isn't necessarily 'wrong'. If I had a guitar already wired the first way I wouldn't necessarily change it - if everything worked okay, and noise wasn't a particular problem then I'd probably leave well alone. Single coils (whether tapped or not) are prone to a certain amount of noise, and if it isn't excessive (particularly in the low output mode) then it's work for a potentially marginal reduction in noise. 

Jez6345789

I was talking to a friend recently about him wanting a tapped humbucker for his Bernie Marsden Se to give him a more single coil sound for some songs. When I was playing around winding pickups I was really focussed on Classic PAF and wound a few Strat sets for projects. Never looked or built coil tapped pickups.

So ultimately is the idea of two completely separate coils or with a Paf style 3 separate coil all wound to there own outputs preferable but more fiddly. 

We talked about the idea of being able to have the full normal paf the 2nd Paf coil with an added number of turns to take it to say 6.5k to give a better single coil sound and possibly a 2nd humbucking effect with the tap and the other coil to give another tone how different or useful I am not sure.

I have not reasearched this yet hence this question.

Ultimately if he can get it off the shelf for fair money then little point in my time tight world getting the winder from the attic and setting it all up get myself able to wind a few decent coils I doubt after 15 years I can remember what I did that I liked from back then, I just remember endless evenings of getting it wrong or ok before it got to a point where I was happy or thought the pickup was comparable to something I liked.

Alegree

Jez6345789 said:

I was talking to a friend recently about him wanting a tapped humbucker for his Bernie Marsden Se to give him a more single coil sound for some songs. When I was playing around winding pickups I was really focussed on Classic PAF and wound a few Strat sets for projects. Never looked or built coil tapped pickups.

So ultimately is the idea of two completely separate coils or with a Paf style 3 separate coil all wound to there own outputs preferable but more fiddly. 

We talked about the idea of being able to have the full normal paf the 2nd Paf coil with an added number of turns to take it to say 6.5k to give a better single coil sound and possibly a 2nd humbucking effect with the tap and the other coil to give another tone how different or useful I am not sure.

I have not reasearched this yet hence this question.

Ultimately if he can get it off the shelf for fair money then little point in my time tight world getting the winder from the attic and setting it all up get myself able to wind a few decent coils I doubt after 15 years I can remember what I did that I liked from back then, I just remember endless evenings of getting it wrong or ok before it got to a point where I was happy or thought the pickup was comparable to something I liked.

That's how my Chameleon humbucker works.

CasperCaster

@Jez6345789 it's an old idea that like many things has been revisited by various people over the years, whether to create better split tones by adding windings to the split coil; to create vintage PAF and hot PAF designs in a single pickup; or variations such as mismatched coils. And of course, if you have the patience/skill you could have multiple taps in either or both coils. I first saw reference to tapped (as opposed to split) humbuckers back in the early eighties - there is a reference to it (six wire humbucker) with diagrams, in Donald Brosnacs book (my copy is from 1983). I also suspect that the PRS 408 pickups use some sort of variation on that theme. Guitarist Magazine installed a Cat's Whisker S-Bucker in their long term review of the new Shergold guitar (the one designed by Patrick Eggle), and Fender are now trying to Patent the idea with their Double Tap humbuckers (I can't see how that will happen given the amount of Prior Art, but we'll see). With respect to humbuckers with taps and splits, in the UK we have the afore mentioned Cats Whisker Pickups, plus Gemini Pickups, and of course @Alegree ;who has posted above - when funds allow I intend to try a Chameleon humbucker myself, as it looks to be a very interesting design.

Jez6345789

Yeah the Don Bronsac book mine got lost in a house move about 15 years ago. Also loads of old stuff Adrian Legg wrote about wiring 12 way rotary switches for endless settings of series parallel in phase out of phase etc etc. Again cranky old Bill Lawerence and his endless quest to tame eddy currents. Nostalgia indeed.

think I might just push my friend to the Chameleon. 

I wish you could buy 408’s I really like mine

As for Fender patenting well it’s america they have corporate lawyer money so will easily get it in the broken US patent market then leverage any small builder who does anything remotely similar.

i will dig in and see what’s out there after seeing the purgatory Alegree went through to get his out the door I simply do not have the time lol.