41G wire compared to 42G

[Brian W.]

I've been considering winding a couple of Strat pickups with 41G wire instead of the usual 42G. It was suggested to me that the bass would be accented and the overall sound would lose clarity and that the 41G is better for lower volume clean tone rather than high volume stuff. Anybody have experience with this gauge of wire??

[Helmholtz]

I'm still curious about insulation thickness and its potential role in capacitance, but even then, I remain skeptical. I've wound a lot of pickups with a lot of different wire gauges and every single time I come back to turn count being king.

Heavier insulation with same turns count may allow to reduce PU capacitance by 50pF or so. But PU capacitance acts in parallel with the guitar cable's capacitance (several hundred pF) and the amp's input capacitance (often around 150pF). All capacitances add up to total effective capacitance.
So the influence of PU capacitance is rather weak. You can emulate the effect of different PU capacitance by using different (length) cables.

[Slight Return]

Heavier insulation with same turns count may allow to reduce PU capacitance by 50pF or so. But PU capacitance acts in parallel with the guitar cable's capacitance (several hundred pF) and the amp's input capacitance (often around 150pF). All capacitances add up to total effective capacitance.
So the influence of PU capacitance is rather weak. You can emulate the effect of different PU capacitance by using different (length) cables.

Interesting. FWIW, capacitance has not varied much in my experiments using single build poly vs. formvar wire, which is the same insulation thickness as heavy build poly wire. I occasionally have gotten lower capacitance, but never near 85pF, which is held to some magical standard for handwound pickups (for no actual reason that I can tell).

My pickups have rather high capacitance most of the time, around 150pF on average, sometimes as high as 186pF after wax potting, on my Strat single coils. Sometimes they're around 120pF. I'm not sure if this has to do with winding tension or pattern. Potting raises the capacitance it seems by around 20pF or 30pF on average. I don't have enough notes or references on Q factor to reliably tell if that changes as well, but have recently started tracking Q after seeing a post Antigua made about it, and how you can check it at the 1kHz setting on an LCR meter.

As long as I keep the turn count the same, they still sound bright and clear, and not muddy at all. This has kept me with single build poly, and skeptical of investing the time and money into experimenting with heavy build poly. I'm tempted, and may experiment with a half pound just to sate my curiosity. But I've already tried Formvar and it's identical to heavy build poly, so I can't really expect it to be any different. I've wound pickups on the same bobbin with plain enamel, Formvar, and single build poly, and could not hear a difference at all in recordings when using the same turn count each time.

I'm an advocate of providing as many specs as possible with pickups, but I'm hesitant to include capacitance, as I feel any customers that would know what it is would be biased towards very low capacitance, and be convinced that a difference of 100pF will somehow vastly change a pickup, or mean that it's inferior. I'm not sure how winding tension and winding pattern affect capacitance, but the more logical, non OCD part of me says it really is not worth worrying about considering that normal variations in pickup capacitance likely have close to zero effect on the tone when you consider the entire circuit the final guitar ends up in (pots, cables, pedals).

Low capacitance seems more like bragging rights to me, but the actual effect on the sound is very questionable.

I've already done many experiments with many different wire gauges, only to find identical results when using the same turn count. If the resulting pickup has the same inductance, basically, it sounds the same, in my experience. Given the same bobbin style, of course, e.g. Strat, Tele, etc. I remain very skeptical of claims that 43 AWG, for example, at the same turn count as 42, has 'more high end' or 'smoother top end' or whatever else people say. I would need to see this backed up with measurements to believe it. I might believe that 43 AWG might be slightly lower output than 42, but this is also just based on non-scientific observation, and I wouldn't be surprised if it wasn't true.

Wire gauge for me is definitely a matter of practicality: when you want to do a serious overwind, or are working with a small bobbin like a Tele neck pickup. 44 AWG is all I can use for noiseless stacked Strat coils, because each coil only has about 1/4" space to wind on, and 43 AWG can't comfortably fit 8,000 turns of wire in that space in my experiments.

The smaller gauges are also very nice for doing tapped pickups, where you want to have a lot more wire for the full coil when the tap already has the bobbin pretty well filled out. For me, that's about it. Same reason 38AWG is used on wah inductors: thinner wire would not fill the bobbin out very well, as most vintage inductors on wah pedals are gonna have around 400 to 500 turns of wire. And thicker wire is easier to tie around those posts when you're done winding. Simple as that, as far as I can tell.

[mozz]

A lot of LCR meters won't give you a good capacitance reading on a basic inductor, i usually calculate it out.

[Antigua]

I came to this understanding with Helmholtz's help; a pickup is a capacitor pas the resonant peak, and so if you set the test frequency high above the resonant peal, the LCR meter will tell you what the capacitance of the pickup is as though it were meant to be a capacitor in the first place. But there's a catch 22 in that a pickup coil might not be purely capacitive beyond the resonant peak, as in this example:



When this coil was wound, the layering was not even, it was wound a lot to one side, then a lot to the other, and apparently that causes an uneven distribution of capacitance along the series of the lumped capacitances, so there are secondary resonances at high frequencies. If you set the LCR meter to 100kHz and measure capacitance, and there happens to be a resonance at 100kHz, the capacitance value will come out very wrong. It would be nice if LCR meters had many more test frequencies, such as 50kHz or 150kHz, etc. so that if by chance there is a secondary resonance, you could step around it. Most machine and hand wound coild seem to be layered evenly enough that these second resonances are sort of rare, and if there is one, it might not be at 100kHz.

Therefore, I consider the capacitance reading from the LCR meter to be highly usable for the fact that the value is delivered very quickly, and when it is accurate, it is very accurate because you don't even have to factor for the 10 to 20pF probe capacitance as you do with an oscilloscope based measurement, but know that there is a non-zero chance the value might be bogus.

[Slight Return]

A lot of LCR meters won't give you a good capacitance reading on a basic inductor, i usually calculate it out.

What's the calculation for capacitance?

@Antigua

Interesting stuff there. Is there any audible difference that would result from such a coil, or does it just give wonky readings?

[freefrog]

A lot of LCR meters won't give you a good capacitance reading on a basic inductor, i usually calculate it out.

FWIW, something like a Tonghui TH2811D set @ 10khz seems to give realistic measurements.

Below is the capacitance measured with it on a humbucker (sorry for the low quality: it's an old photo took in the lab of my friend winder, then printed on paper ten years ago).



210.74pF (including +/- 130pF of braided shielded wire). It's roughly on par with the measurement done by Prof. Steven Errede on a Gibson 57 Classic+, for example. And it matched our calculations...

That being said to share the reference of a useful lab meter. :-)

[freefrog]

the more logical, non OCD part of me says it really is not worth worrying about considering that normal variations in pickup capacitance likely have close to zero effect on the tone when you consider the entire circuit the final guitar ends up in (pots, cables, pedals).

Low capacitance seems more like bragging rights to me, but the actual effect on the sound is very questionable.

At first glance, yep, the stray capacitance of a pickup must be drowned in overall capacitance. Now, a low coil capacitance is not exactly negligible IMHO/IME when volume/tone controls are lowered...

More later if time permits - and if I succeed to formalize something useful for this topic. :-)

[Antigua]

What's the calculation for capacitance?

@Antigua

Interesting stuff there. Is there any audible difference that would result from such a coil, or does it just give wonky readings?

I think I answered this before the moderator moved this thread to this new corner of the forum, but if you determine L and peak frequency, you can just plug the values into here https://www.omnicalculator.com/physics/rlc-circuit and the C automatically fills out. Then you just have to subtract the capacitance of the meter than you used to get the peak frequency, which is usually like 10pF to 20pF for a probe in 10x mode. I have a lot of faith in the DE-5000 because it confirmed capacitance measurement from the L and peak f, minus 10pF to 15pF. Likewise, if you use a meter and measure the L and 100Hz and the C at 100kHz, then use that same website to find peak f, it will likely be more accurate than the bode plotter, which had reported a peak capacitance that included the probe capacitance. Also not that if the DE-5000's test leads are touching together, that alone adds about 5pF, so make sure none of the leads or wires are side by side or overlapping. In the case of a humbucker with a braided cable, I usually get 70pF for 12" of braided lead cable, so you could find the true peak frequency from L and C, less the 70pF of the braided cable, and not have to go through the trouble of removing the lead wire. All of this assumes the resonant peak is important, but because so much capacitance will be added via the guitar cable, the actual resonant peak is almost a triviality, useful for finding L if you know C, and vice versa.

[Mike Sulzer]

I've been considering winding a couple of Strat pickups with 41G wire instead of the usual 42G. It was suggested to me that the bass would be accented and the overall sound would lose clarity and that the 41G is better for lower volume clean tone rather than high volume stuff. Anybody have experience with this gauge of wire??

Yes, you cannot get as many turns on, and so the expected inductance is lower and you lose some volume. The resistance will be lower and so the Q is higher (significantly so if other losses are low). You expect a brighter sounding pickup unless you move the resonance so high that it is out of range of significant string harmonics or the range of the guitar electronics, especially the speaker.

[bassystem]

I've been considering winding a couple of Strat pickups with 41G wire instead of the usual 42G. It was suggested to me that the bass would be accented and the overall sound would lose clarity and that the 41G is better for lower volume clean tone rather than high volume stuff. Anybody have experience with this gauge of wire??

so have you tried? results?

Also, does anybody knows where can I find some common measure for most commom pickups, eg for p bass, j bass, strat, tele...(I mean dimensions of bobin, magnets, n-s and winding directions etc)

Thanks

[StarryNight]

I came to this understanding with Helmholtz's help; a pickup is a capacitor pas the resonant peak, and so if you set the test frequency high above the resonant peal, the LCR meter will tell you what the capacitance of the pickup is as though it were meant to be a capacitor in the first place. But there's a catch 22 in that a pickup coil might not be purely capacitive beyond the resonant peak, as in this example:

[ATTACH=CONFIG]58415[/ATTACH]

When this coil was wound, the layering was not even, it was wound a lot to one side, then a lot to the other, and apparently that causes an uneven distribution of capacitance along the series of the lumped capacitances, so there are secondary resonances at high frequencies. If you set the LCR meter to 100kHz and measure capacitance, and there happens to be a resonance at 100kHz, the capacitance value will come out very wrong. It would be nice if LCR meters had many more test frequencies, such as 50kHz or 150kHz, etc. so that if by chance there is a secondary resonance, you could step around it. Most machine and hand wound coild seem to be layered evenly enough that these second resonances are sort of rare, and if there is one, it might not be at 100kHz.

Therefore, I consider the capacitance reading from the LCR meter to be highly usable for the fact that the value is delivered very quickly, and when it is accurate, it is very accurate because you don't even have to factor for the 10 to 20pF probe capacitance as you do with an oscilloscope based measurement, but know that there is a non-zero chance the value might be bogus.

Sorry if this derails the conversation slightly but can you explain the graph briefly? The corner numbers identify peaks at 10k and 86k hz but I only see this giant peak at 153khz. Also, I didn’t realize sweeping that high was necessary to get usable measurements. Is this specifically for getting capacitance measurements? I thought resonant peaks were around 8khz +/-

[Helmholtz]

Sorry if this derails the conversation slightly but can you explain the graph briefly? The corner numbers identify peaks at 10k and 86k hz but I only see this giant peak at 153khz. Also, I didn’t realize sweeping that high was necessary to get usable measurements. Is this specifically for getting capacitance measurements? I thought resonant peaks were around 8khz +/-

The main PU resonance is the large peak at 10.4kHz. 153kHz is just the accidental position of the vertical cursor. Peaks above 20kHz are not audible.
The wide band sweep was done to see if the LCR meter can be used to measure capacitance at 100kHz or not. In the example shown, the second resonance around 100kHz would interfere with the cap measurement.

The needle spikes seem to be measuring artifacts and should be ignored.

[Antigua]

Sorry if this derails the conversation slightly but can you explain the graph briefly? The corner numbers identify peaks at 10k and 86k hz but I only see this giant peak at 153khz. Also, I didn’t realize sweeping that high was necessary to get usable measurements. Is this specifically for getting capacitance measurements? I thought resonant peaks were around 8khz +/-

To be honest I don't know why the capacitance test has to be at a very high frequency, but several people with EE backgrounds suggest that the test freq should be about 10 times the peak resonance, which 100kHz would be. I'm guess the reason is that pickups have a low Q factor, so a frequency well beyond the resonance ensures that's the pickup is purely capacitive. Unfortunately, the DE-5000 and other affordable LCR meters only have 100kHz high testing frequencies, so I can't compare and contrast the accuracy at a variety of frequencies. And, as mentioned, the plot shows that the pickup is non-ideal at 100kHz, those two smaller peaks show that the pickup becomes inductive again at those higher frequencies, including in the test range of 100kHz. If someone makes an LCR meter with a wider variety of test frequencies, that issue could be overcome.

The secondary resonances come from the coil being wound in an especially non ideal manner, which can lead to there being a "coil within the coil", where a portion of the coil will have LC resonance independently from the rest of the coil. It's not unlike having two completely separate coils in series, which will also exhibit this same sort of second resonance. Purely machine wound pickups are less likely to have these anomalies than pickups where the wire was hand guided, and allowed to "clump up" rather than lay in an even manner. Some make the claim that scatter wound pickups sound special, but this is all that happens, that pickup becomes less predictable at frequencies that are beyond both human hearing, and the operational range of guitar speakers.

[Helmholtz]

To be honest I don't know why the capacitance test has to be at a very high frequency, but several people with EE backgrounds suggest that the test freq should be about 10 times the peak resonance, which 100kHz would be. I'm guess the reason is that pickups have a low Q factor..

An ideal capacitor has an impedance response of -6dB/octave or -20dB/decade. Far above the resonance a parallel resonant circuit like a PU behaves purely capacitive. Closer to the resonance the decay is steeper, so a C-meter would read a higher "apparent" capacitance.
For PUs having a smooth -6dB/octave slope at 100kHz I could confirm the LCR capacitance measurements at 100kHz with a 40MHz HP impedance analyzer.
The resonance Q of the PU doesn't matter as long as there is a -6dB/octave slope at 100kHz.