Bill Lawrence Micro-coil Pups?

[TNO]

"As with his SCN and NS series, it is my understanding that Bill uses the properties of various magnets/materials to create eddy-currents which influence the tone, and focus the field into the coils and away from the strings. It's really quite incredible, and takes a very thorough understanding of all the material's properties, how they interact, the desired target frequency curve, and the experience to put it all together."

That's all fine and good but these have about double the magnetic pull compared to a standard A3 pickup. This is based on my uber-scientific "touch a polepiece with a screwdriver tip and see how well it sticks" method.

They may be quiet, toneful pickups but they are going to dampen string vibration if set too close to the strings.

[Narcoleptigon]

Ah, good to know. A5 has about double the strength of A3. My L280S's are about that strong. Any stronger and it would be an issue. Again, it sounds like Bill knows what he is doing.

[Derek Kiernan]

Originally Posted by TNO

That's all fine and good but these have about double the magnetic pull compared to a standard A3 pickup. This is based on my uber-scientific "touch a polepiece with a screwdriver tip and see how well it sticks" method.

They may be quiet, toneful pickups but they are going to dampen string vibration if set too close to the strings.

I've set them incredibly close using Blue Steels to experiment, no issues. I'm confident they don't have that much pull.

[Narcoleptigon]

Maybe, like with the NF(not NS, my bad) and SCN series, the opposing field drawn up through the coil and back into the pole pieces equalizes the force on either side of the pole, diminishing string pull. The north and south facing poles of humbuckers have the same effect.

[Voicing 13]

Just to add,

tested today with florescent light, a tele with micro coils and a Squier standard . Got on a chair and I put the micro coil tele close to the light almost no noise. Did the same with the Squier but not on the chair, lots of noise immediately. Significant difference between the two in terms of 60cycle hum.

[Derek Kiernan]

Thanks for sharing! I've played next to florescent lights and old CRT computer monitors with noticeable but negligible amounts of noise.

[Boolywho]

So, aside from the great tone, are these things supposed to be close to noiseless?

Am I correct in thinking these microcoils are not humbucking by design, but rather that because they have a very small coil, they pick up less interference?

Just trying to figure out what these things are all about. Thanks!

[Derek Kiernan]

That's a large part of it. The coil is uses much finer gauge wire than traditional pickups, which increases coil density (raising voltage output) as it decreases surface area (which would otherwise act as an antennae). The small coil size allows for Bill's very finely tuned magnetic circuit, pushing overall efficiency even further over conventional designs.

The micros also have a bit less inductance than conventional designs, a bit more high end, and considerably more note fundamental. There's no harsh, sharp or nasal quality to them. Above all, they're really really clear and defined :D

[Narcoleptigon]

Thanks, DK. Regarding voltage increase, I wonder if it's not the increased under-coil magnetism that creates the higher voltage? I don't fully understand the principles, but wouldn't smaller wire and less windings mean less wire surface area, therefore less voltage?

I estimate that there is somewhere in the area of 1/16th of the total wire surface of a standard 43 gauge wire Strat PUP, equating to about 1.5k DC for that wire gauge. As well as broadening the frequency spectrum, that alone should decrease hum by a very significant 12db .

[Derek Kiernan]

The surface area I mentioned is the exterior of the coil, not the wire before it is wound. Turns per square is absolutely critical. I don't remember the exact numbers, so forgive me if I have to correct them:

A traditional Fender-style pickup has something in the neighborhood of 180 turns per square (for a well executed example). The microcoil achieves in surplus of 400. This also gets all that density in a much smaller area where the magnetic field is stronger, dramatically increasing efficiency.


Consider the counter example. If winding coils with really thick gauge wire were preferable to increase voltage output and you wound one with the same number of turns, you'd wind up with a much more massive coil. It seems intuitive that this pickup isn't as useful or efficient - all the windings past the dimensions of a more conventional pickup are where the magnetic field is substantially weaker, too far away to be of use. The change is actually worse than that in several ways:

1) The larger coil now adds noise (thanks to surface area).
2) The newly added dimensions to the coil are dramatically less efficient (less voltage output proportionally) than the original dimensions of the conventional pickup.
3) The coil is way too large to have the coil phase-aligned with the magnetic field. What this means is that you'll get absolutely bizarre phase cancellations due to how poorly the pickup is design, smearing the definition and introducing negative tonal qualities.

That's all before you even discuss the density question directly. It's so intuitive that no one on the market tries selling pickups with 30 or 20 gauge wire instead of 42 gauge wire because the results would be absolutely absurd. They would be inefficient, low output, incredibly distorted, awful sounding pickups.

In consideration of point number (2), the same thing is true of all the "overwound" pickups on the market. The extra wire does almost nothing to increase voltage output. What it does do is increase inductance, which is important because the resulting downward shift of the coloring resonance will often raise the output.

But if we know where the resonance should go, inductance is actually a negative quality - increases in inductance make it both much harder to predict which capacitor you should use on the tone pot for coloration and takes away consistency as you switch between cables of varying capacitance. Since inductance and cable capacitance decide where the resonance are, and the highend drops off dramatically above the resonance, it'd be best to minimize inductance (and cable capacitance) to get the most highs to the amplifier and add coloration at the tone pot (which will let you keep your highs if it's not down all the way). You end up with pleasing coloration and won't fall into awful ranges (like 3-4 kHz) that lend themselves to icepick.




After you think about this, it's clear that the game is to get the least inductance and most voltage output, as well as preserving phase relations that achieve the least distorted tonality, while maximizing responsiveness and versatility with current day guitar amplifiers. This is exactly what the microcoil design does with flying colors and why it's such an incredible development in the history of pickup design.

[TNO]

Well, I got mine in yesterday. Played around a lot with pickup height and pulled them out. They are impressively quiet and have a true single-coil tone. The problem for me is they don't have enough lower mids and the highs have a brash quality. Not a pickup that works well with overdrive for ME.

Esoteric arguments to the contrary, microcoils really do have a crazy amount of magnet pull coming off the top of the polepiece screws.

[Derek Kiernan]

It's not directly relevant how much magnetic pull there is exactly at the top of the pole (/screw), it's how much there is where the strings are. If you take an example of two cylindrical Alnico magnets similarly charged but of different lengths, the longer magnet will have more pull higher above the top even if they have equal pull on top of the pole. The magnetic design has incredible importance in this context that you can't deduce by sticking a screwdriver to the pickup.

I'd really recommend turning the mids up and the treble down, and most likely rolling back on the tone pot.

[Alex M]

Derek, rather than readjustin the customary amp or guitar settings, is there a capacitor or wiring solution to get these pups closer in tone to traditional single coils? I think that's what TNO is looking for, and you seem to have a pretty thorough understanding of how to the microcoils operate. Any suggestions for wiring tricks to tame the highs and bring out the mids, or otherwise bring these pups more in line with the traditional tone?

[Derek Kiernan]

I'll repost what I wrote on WildeGate a while ago here:


There have been some questions floating around about how to choose capacitors to color the microcoil's tonality. I wrote this up as a short, rough guide for exploring this with the Strat and Tele standard sets. I'm sure Bill will come out with both better explanations and better suggestions when he has the time for that sort of thing (Get well soon Bill!)

Some pretext from Bill's cable description page:
1. The higher the capacitance of a cable, the less highs reach the amplifier.
2. High-capacitance cables shift the resonance towards the lower frequencies which dramatically alters tone. For example, Jimi Hendrix used a coiled cord with 3,000 picofarads (.003 microfarads), shifting the resonance below 2,000 Hertz on his Strats. This was the secret of Jimi's tone. Shifting the resonance frequency at 2,000 Hertz has a similar effect to a midrange boost. However, when he recorded and needed a typical Strat sound for some tracks, Jimi switched to a short, low-capacitance cable.
3. There are some very expensive high-capacitance cables on the market with a sound you might like for some tunes, but then you are stuck with that one sound. Using a low-capacitance cable, you can easily change the circuit capacitance by using a push-pull tone control to switch capacitors -- one capacitor for clean sounds and another for distortion. This allows you to choose the right capacitor values to match the pickups, aiming for a 600-700 Hertz resonance for clean sound and a 1500-2200 Hertz resonance for distortion.

Here's are some general descriptors for sounds or uses of different frequency ranges on guitar.
10 kHz = air
6+ kHz = sweet highs
4.2-4.5 kHz = sparkle, classic bell tone
3-4 kHz = bright, harsh, "icepick"
2.3-2.6 kHz = warm
1.8-2.1 kHz = aggressive, power ++ on bridge
1.4-1.6 kHz = darker, "jazzy"
1.0-1.2 kHz = distortion


The following is organized by
1. desirable coloring resonances in the (upper) midrange for the bridge pickup
2. the corresponding neck/middle resonance with identical capacitance
3. total capacitance needed in parallel (tone pot + cable capacitance)

The standard Strat set is 2H neck/middle, 2.8H bridge. The Tele set is 2H neck and 2.8H bridge as well. Instead of getting the capacitance from the cable, as Hendrix did, it's preferable to add in color at the tone pot. This is to 1) prevent the rapid dropoff of high-end after the resonance, 2) control the level of accentuation to the resonance, in a balance with 3) the level of the high-end after the resonance. Cable capacitance is helpful to know, but not critical. (Bill's is 19 pF/ft, so a 12 ft cable is around 230 pF. Average guitar cable seems to be between 40-55 pF/ft.) You don't need to land the resonance very precisely to get the effect, so less than 100 Hz in either direction isn't going to make a significant perceivable difference. I still prefer to minimize cable capacitance, to ensure we can get the most high end extension to the amplifier as possible, but it's not essential when talking about adding coloration.

The numbers:

2.6 kHz bridge
3.1 kHz neck
1.3 nF

2.4 kHz bridge
2.8 kHz neck
1.6 nF

2.2 kHz bridge
2.6 kHz neck
1.9 nF

2.0 kHz bridge
2.35 kHz neck
2.3 nF

1.8 kHz bridge
2.1 kHz neck
2.8 nF

1.6 kHz bridge
1.9 kHz neck
3.5 nF

1.4 kHz bridge
1.65 kHz neck
4.6 nF

1.2 kHz bridge
1.4 kHz neck
6.3 nF

1.0 kHz bridge
1.2 kHz neck
9 nF

650 Hz bridge
750 Hz neck
22 nF


Hopefully some of you will have a bit of fun trying out different capacitor values, which of course you can add in parallel to each other. You may want to use one tone pot on a Strat for a warm-bright resonance on the neck position while using the other tone pot with the bridge as you explore 2 kHz and below. Results will vary substantially with the speaker used, so check to see the speaker doesn't already place a strong (peaky) resonance where you're considering. You also won't hear what the speaker's not producing! The beautiful highs at 6+ kHz aren't present with (most) conventional guitar speakers.


Two additional important notes:

The capacitor's effect will come into play on the tone pot at about 4 or so, so you may find your "sweet spot" at 3 or below, but likely before the "bottom of the pot" where you'll get a strong peak and then rapid dropoff of high-end above the resonance.

You may also want to start with a much more neutral tone stack setting than you're used to. The micros have plenty of high end brilliance and strong fundamental, so you'll want to rethink how you set the amplifier. With a Fender-style tone stack, try maxing the mids, with the bass between 2-4 and treble 1-3. It'll take a little while to get adjusted perfectly, in combination with the coloration selection and pickup heights, but it all sounds pretty amazing :D

[Derek Kiernan]

Originally Posted by Alex M

Derek, rather than readjustin the customary amp or guitar settings, is there a capacitor or wiring solution to get these pups closer in tone to traditional single coils? I think that's what TNO is looking for, and you seem to have a pretty thorough understanding of how to the microcoils operate. Any suggestions for wiring tricks to tame the highs and bring out the mids, or otherwise bring these pups more in line with the traditional tone?

So in short, yes and no. You still want to readjust the tone stack (perhaps dramatically!), but most will benefit considerably from using a capacitor on the tone pot to get the coloration too - you'd both be able to control the balance of highend and coloration as well as avoid unflattering resonances. Unless the cable is extremely high capacitance, it'd be hard to get the resonance in the wrong place with just the cable.

[Voicing 13]

Derek, thank you for sharing your knowledge and insights on pickups.

I think it's important to play around with amp settings as well. I was reminded of this by a friend a while back and realized that my settings were in functions of "not to have to think about it." This allowed me some more tonal explorations. Now I'm talking about me here, no reference to previous posts.

As well with these pups, I've tried Derek's settings and found very usable sounds while playing with the tone pot; I normally never touch the thing. That being said I am looking to make this guitar versatile.

[Narcoleptigon]

TNO, did you find your assessment of tone to be true in all PUP positions?

A low-C cable, and 250k pots would sound smoother. In a Tele, certain bridge-plate materials will negatively affect tone.

[TNO]

Yes, the tonal signature of the pickup was there in all positions. Running 250k pots and a .047 cap. I've had issues with BL's humcancelling pickups and standard bridge plates. I think the microcoil design works fine in this regard. Didn't have an issue with "stratitis" but it seemed like the sustain of the guitar was reduced (it has a solid spruce body that just rings and rings). I shielded the guitar before installing the pickups and when I went back to my Rumpel Black Ropes I found that hum and buzz was pretty effectively nuked.

It's a cool design but I suspect the neo magnets are what's affecting the tone in a way I don't care for. Would be interesting to know how alnico magnets would work??

[Narcoleptigon]

I dunno. I think Alnico wouldn't provide nearly enough power, or something. I guess the MC's don't suite your purposes. I'm in a quandary about replacing my L280's. I like certain things about them so much.

[telerocker1988]

Gotta try these! Love the Keystones.