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Post by antigua on Jan 2, 2020 1:42:44 GMT -5
I ordered eight Strat pickups from a fellow on TDPRI who goes by "kingvox", four wound with red coated "Plain Enamel" wire and four with clear coated "Enameled Copper" wire, from Remington. I measured the electrical values of all eight pickups: I don't know much about his winding process, except that he used the same process for all eight pickups. These are the specs: Plain Enamel #1 L: 2.316H C: 106.84pF R: 6.109k ohms
Plain Enamel #2 L: 2.440H C: 106.95pF R: 6.137k ohms
Plain Enamel #3 L: 2.386H C: 96.33pF R: 6.064k ohms
Plain Enamel #4 L: 2.173H C: 101.02pF R: 5.870k ohms
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Enameled Copper #1 L: 2.213H C: 143.53pF R: 5.901k ohms
Enameled Copper #2 L: 2.367H C: 111.14pF R: 5.843k ohms
Enameled Copper #3 L: 2.248H C: 122.58pF R: 5.847k ohms
Enameled Copper #4 L: 1.866H C: 127.35pF R: 5.451k ohmsThese are the specs provided by the manufacturer, which reveals that the enameled copper wire is actually coated with polyurethane. I'm not sure why they don't call it "polyurethane coated wire". www.remingtonindustries.com/magnet-wire/magnet-wire-plain-enamel-42-awg-5-spool-sizes/Wire Type: Plain Enamel Copper Wire Diameter: 0.0027" Color: Brown Insulation: Plain Enamel NEMA Description: MW-1-C Build: Single Min-Nom Temperature Rating: 105°C (221°F) www.remingtonindustries.com/magnet-wire/magnet-wire-42-awg-enameled-copper-5-spool-sizes-2-colors/Wire Type: Enameled Copper Wire Diameter: 0.0026" Color: Natural / Red Insulation: Solderable Polyurethane NEMA Description: MW-79-C Build: Single Min-Nom Temperature Rating: 155°C (311°F) The pickup's specs are not real solid across the four samples of each, but the "plain enamel" pickups showed a bit less capacitance than the "enameled copper wire" /polyurethane . According to the specs, the polyurethane coated wire is a tiny bit thinner than the plain enamel, and it's possible that a smaller insulation build accounts for the higher capacitance. Guessing aside, the results show that the electrical values aren't divergent to any significant degree, and that whatever the dielectric constant is of these materials, they're pretty close. According to this www.iewc.com/assets/specsheets/MW78C-16-S_Specification.PDF the dielectric constant of polyurethane is 3.7, while the dielectric constant of formvar is 7.4. I can't find a dielectric constant for "plain enamel", but this page www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm lists "enamel" at 5.1. All together the capacitance of like for like coils isn't likely to vary much beyond 50pF to 100pF worst case scenario. The lowest I've measured for a 42 AWG Strat pickup was around 85pF, and on rare occasion as high as 200pF, but more often around ~120pF, and within that range is a variety of differences, such as different wire insulation, machine versus hand guided and tensioned, wax potted and non-potted.
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Post by pablogilberto on Jan 4, 2020 7:04:49 GMT -5
All together the capacitance of like for like coils isn't likely to vary much beyond 50pF to 100pF worst case scenario. The lowest I've measured for a 42 AWG Strat pickup was around 85pF, and on rare occasion as high as 200pF, but more often around ~120pF, and within that range is a variety of differences, such as different wire insulation, machine versus hand guided and tensioned, wax potted and non-potted. Let's say, two pickups have the same DCR and Ls values. Will a variation of +/- 20pF Capacitance make a noticeable difference in tone? Do we generally want a less than 100pF Cp capacitance on pickups? What are the effects of machine versus hand guided and tensioned, wax potted and non-potted when it comes to the capacitance of the pickups? Thank you
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Post by antigua on Jan 4, 2020 17:29:38 GMT -5
All together the capacitance of like for like coils isn't likely to vary much beyond 50pF to 100pF worst case scenario. The lowest I've measured for a 42 AWG Strat pickup was around 85pF, and on rare occasion as high as 200pF, but more often around ~120pF, and within that range is a variety of differences, such as different wire insulation, machine versus hand guided and tensioned, wax potted and non-potted. Let's say, two pickups have the same DCR and Ls values. Will a variation of +/- 20pF Capacitance make a noticeable difference in tone? Do we generally want a less than 100pF Cp capacitance on pickups? What are the effects of machine versus hand guided and tensioned, wax potted and non-potted when it comes to the capacitance of the pickups? Thank you In general, a guitar cable's capacitance is about 40pF per foot, so adding or removing 20pF is like adding or removing 6" of guitar cable. If you load an RLC calulator like this www.calctool.org/CALC/eng/electronics/RLC_circuit and enter 3 henries for the inductance, 600pF for the capacitance (some pickup capacitance and a of cable capacitance) and 6k for the DC resistance, you get a resonant peak of 3751.32 Hz, which is typical of a Strat pickup. Dropping the capacitance to 580 increases the peak frequency to 3815.45Hz, increasing it 620pF decreases the frequency to 3690.32Hz, so that's only about 60Hz +/-. An electric guitar only produces sound at that frequency when the string is plucked, and then it decays to nothing within a fraction of a second, so these tiny changes don't change the overall sound of the guitar, they change the "pick attack", a higher resonant peak makes it easier to hear the pick against the strings. One reason guitarists like pickups with a low peak, like P-90s, is that they effectively cut off the pickup attack sounds due to their limited frequency response. A different of 100Hz in that range only has a small effect on the perception of the pick attack. On the other hand, if you drop from 500Hz down to 400Hz, that difference because a lot more noticeable because more of the sustained output falls within that frequency range, so the attenuation is a lot more apparent. Therefore, the brighter a pickup is, the shorter the amount of time per plucked note that the capacitance has any effect, and so the less defining it is of the overall tone. On the other hand, if you use a really long guitar cable, and bump the capacitance up to 1,000pF, the resonant peak drops to 2905.76Hz, which is getting down into the range associated with humbuckers and hot single coils, that attenuation of 700Hz of content is much more easily appreciated. Therefore there is nothing much you can do to a pickup design-wise to where the capacitance is ever critically important, because at most you can increase the capacitance by 100pF with thin insulation or wax potting or whatever, it just won't change the resonant peak by a significant amount. I don't ignore capacitance though, because when you add up all the sources of capacitance, it can become significant, so it's good to save where you can. One thing I've discovered with the wax potting is that it increases the capacitance, but the tension of the coil impacts how much wax the coil will permit. If the coil is wound tighter, the capacitance will increase because there is less air between the turns, but it will also permit less wax when it's potted, where as a loose coil has less capacitance because there is more air, but then when it's wax potted, it uptakes more wax because there is more air to be displaced with wax, and so no matter which approach is taken, you end up with similar capacitance. Probably the best approach is "light wax potting", where an attempt is made to not allow the wax to fully permeate the coil, only the outermost turns, because I found through testing that it's the outer turns that are responsible for microphonics guitarnuts2.proboards.com/thread/8750/pure-paraffin-wax-potting-pickup. The inner turns of the coil are under enough pressure that they're immobilized with or without wax, and so it's not necessary for the wax to fully permeate the coil.
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Post by pablogilberto on Jan 4, 2020 20:02:54 GMT -5
Let's say, two pickups have the same DCR and Ls values. Will a variation of +/- 20pF Capacitance make a noticeable difference in tone? Do we generally want a less than 100pF Cp capacitance on pickups? What are the effects of machine versus hand guided and tensioned, wax potted and non-potted when it comes to the capacitance of the pickups? Thank you In general, a guitar cable's capacitance is about 40pF per foot, so adding or removing 20pF is like adding or removing 6" of guitar cable. If you load an RLC calulator like this www.calctool.org/CALC/eng/electronics/RLC_circuit and enter 3 henries for the inductance, 600pF for the capacitance (some pickup capacitance and a of cable capacitance) and 6k for the DC resistance, you get a resonant peak of 3751.32 Hz, which is typical of a Strat pickup. Dropping the capacitance to 580 increases the peak frequency to 3815.45Hz, increasing it 620pF decreases the frequency to 3690.32Hz, so that's only about 60Hz +/-. An electric guitar only produces sound at that frequency when the string is plucked, and then it decays to nothing within a fraction of a second, so these tiny changes don't change the overall sound of the guitar, they change the "pick attack", a higher resonant peak makes it easier to hear the pick against the strings. One reason guitarists like pickups with a low peak, like P-90s, is that they effectively cut off the pickup attack sounds due to their limited frequency response. A different of 100Hz in that range only has a small effect on the perception of the pick attack. On the other hand, if you drop from 500Hz down to 400Hz, that difference because a lot more noticeable because more of the sustained output falls within that frequency range, so the attenuation is a lot more apparent. Therefore, the brighter a pickup is, the shorter the amount of time per plucked note that the capacitance has any effect, and so the less defining it is of the overall tone. On the other hand, if you use a really long guitar cable, and bump the capacitance up to 1,000pF, the resonant peak drops to 2905.76Hz, which is getting down into the range associated with humbuckers and hot single coils, that attenuation of 700Hz of content is much more easily appreciated. Therefore there is nothing much you can do to a pickup design-wise to where the capacitance is ever critically important, because at most you can increase the capacitance by 100pF with thin insulation or wax potting or whatever, it just won't change the resonant peak by a significant amount. I don't ignore capacitance though, because when you add up all the sources of capacitance, it can become significant, so it's good to save where you can. One thing I've discovered with the wax potting is that it increases the capacitance, but the tension of the coil impacts how much wax the coil will permit. If the coil is wound tighter, the capacitance will increase because there is less air between the turns, but it will also permit less wax when it's potted, where as a loose coil has less capacitance because there is more air, but then when it's wax potted, it uptakes more wax because there is more air to be displaced with wax, and so no matter which approach is taken, you end up with similar capacitance. Probably the best approach is "light wax potting", where an attempt is made to not allow the wax to fully permeate the coil, only the outermost turns, because I found through testing that it's the outer turns that are responsible for microphonics guitarnuts2.proboards.com/thread/8750/pure-paraffin-wax-potting-pickup. The inner turns of the coil are under enough pressure that they're immobilized with or without wax, and so it's not necessary for the wax to fully permeate the coil. Thanks for this valuable information. I'm learning a lot. Some follow-up questions and clarifications: 1. "One reason guitarists like pickups with a low peak, like P-90s, is that they effectively cut off the pickup attack sounds due to their limited frequency response." - What do you mean by the limited frequency response of P-90s? 2. "A different of 100Hz in that range only has a small effect on the perception of the pick attack. On the other hand, if you drop from 500Hz down to 400Hz, that difference because a lot more noticeable because more of the sustained output falls within that frequency range, so the attenuation is a lot more apparent. Therefore, the brighter a pickup is, the shorter the amount of time per plucked note that the capacitance has any effect, and so the less defining it is of the overall tone. " - I thought that the resonant peak gives the overall characteristic of the pickup. How much deviation in resonant freq (Hz) do I need to have a noticeable difference in the overall sound? - What do you mean by 500Hz to 400Hz? Do you mean looking what happens at the frequency response curve at that those points? Are they not going to be more or less flat? 3. Using the RLC calculator, it is apparent that only the L and C affects the resonant frequency. What does R do? Say given some pickup with some RLC values, what will be the difference in freq response and sound if I have another set with the same LC values with R changed to +/- 500ohms? 4. If I have some target RLC values for a Strat pickup, what's the best strategy to wind a pickup with the closest possible specs? Is it more about the cable specs or winding style? Ideally, my goal is this: DCR - 5.95k ohms Ls - 2.4H Cp - 110pF Thank you!
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Post by antigua on Jan 4, 2020 20:40:14 GMT -5
Thanks for this valuable information. I'm learning a lot. Some follow-up questions and clarifications: 1. "One reason guitarists like pickups with a low peak, like P-90s, is that they effectively cut off the pickup attack sounds due to their limited frequency response." - What do you mean by the limited frequency response of P-90s? 2. "A different of 100Hz in that range only has a small effect on the perception of the pick attack. On the other hand, if you drop from 500Hz down to 400Hz, that difference because a lot more noticeable because more of the sustained output falls within that frequency range, so the attenuation is a lot more apparent. Therefore, the brighter a pickup is, the shorter the amount of time per plucked note that the capacitance has any effect, and so the less defining it is of the overall tone. " - I thought that the resonant peak gives the overall characteristic of the pickup. How much deviation in resonant freq (Hz) do I need to have a noticeable difference in the overall sound? - What do you mean by 500Hz to 400Hz? Do you mean looking what happens at the frequency response curve at that those points? Are they not going to be more or less flat? 3. Using the RLC calculator, it is apparent that only the L and C affects the resonant frequency. What does R do? Say given some pickup with some RLC values, what will be the difference in freq response and sound if I have another set with the same LC values with R changed to +/- 500ohms? 4. If I have some target RLC values for a Strat pickup, what's the best strategy to wind a pickup with the closest possible specs? Is it more about the cable specs or winding style? Ideally, my goal is this: DCR - 5.95k ohms Ls - 2.4H Cp - 110pF Thank you! 1) P-90's have a low resonant peak, with 47-pF load the peak is around 2kHz, half that of a Strat pickup. You don't hear much pick attack with P-90's and their tone is darker, more mid-range overall. IIRC, they contain about 10k turns of 42AWG, where as a Strat pickup is usually close to 8k turns, before even taking into account the steel screws versus the AlNiCo pole pieces. 2) IME the change needs to be somewhere between 250Hz and 500Hz order to notice a difference. On the low end to be noticeable, on the high end to be meaningful. I've experimented with caps a lot, and I can usually hear a difference when I've added or removed enough capacitance to move the frequency by about 400Hz. Also in the database of pickups, comparing "hot" and "vintage" pickups, a lot of pickups can be within 400Hz of each other and they're all described as "vintage" but once the frequency is about 400Hz below that median, they tend to be called "hot" or "dark". For example, a typical PAF is around 2.5kHz to 3kHz, but a hot "JB" humbucker is around 2kHz, or a vintage output Strat pickup is around 4kHz, but a hot Strat pickup is closer to 3.5kHz, but as low as 3kHz. By 500Hz to 400Hz I mean the sound difference if the resonant peak was 500Hz, but dropped to 400Hz through added capacitance. 3) Resistance only effects the Q factor. It's not important with respect to the pickup, because the series resistance has a small effect on the Q factor. Adding 500ohms of series resistance wouldn't change the sound in any audible way. You would have to add maybe 10k ohms to begin to notice a difference. But resistance is important with respect to the volume and tone controls, because in that position within the circuit they have a greater effect on the Q factor. 4) If youre winding a Strat pickup, it makes sense to think primarily about the inductance and not worry about the resistance or the capacitance. I haven't wound many pickups so I don't know what strategy works best for hitting a particular target, but I know that fully machine made pickups tend to be the most consistent. When I wind Strat pickups to 8,000 turns they usually end up close to 2.4 henries and 6.0k DC resistance. That seems to be an industry standard spec point. It's so common that I would sooner just buy them rather than make the myself.
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Post by pablogilberto on Jan 4, 2020 21:10:13 GMT -5
By 500Hz to 400Hz I mean the sound difference if the resonant peak was 500Hz, but dropped to 400Hz through added capacitance. How do we move the resonant frequency of a pickup to around 500Hz to 400Hz? I thought they are usually around 2kHz to 4kHz. Thanks!
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Post by antigua on Jan 5, 2020 2:28:31 GMT -5
By 500Hz to 400Hz I mean the sound difference if the resonant peak was 500Hz, but dropped to 400Hz through added capacitance. How do we move the resonant frequency of a pickup to around 500Hz to 400Hz? I thought they are usually around 2kHz to 4kHz. Thanks! When you have a tone control set to "0", the cap is fully in parallel with the pickup, and the Q factor is almost fully restored, so essentially you have a pickup with a resonant peak around 500kHz with a 22nF cap, or closer to 400Hz with a 47nF cap, with a Strat style pickup. If the pickup has a higher inductance, like a PAF style humbucker, 22nF caps are often chosen in order to keep the peak closer to 500Hz as much lower than that, it becomes very muddy. You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. It's that lower resonant peak that creates the impression of a humbucker pickup, as the Strat-sized humbucking pickup is physically too thin to actually recreate the tone of a PAF style pickup. They could pretend it was a P-90 if they wanted, but the'59 PAF is beloved by guitarists, so of course they call it that.
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Post by stratotarts on Jan 5, 2020 9:53:39 GMT -5
The downshift of the peak with the tone capacitor can justify having a guitar mounted tone control - the interaction of the tone circuit with the pickup is unlike the independently responsive tone controls of the amp. Of course, nowadays an inline equalizer can also do almost anything tonally, if the amp doesn't already cover it. However, that requires a lot of knob twiddling. As the tone volume control resistance decreases when it is turned down, the Q also increases as the resonant frequency drops. It's just serendipity that such a simple circuit also happens to have a sonically useful response.
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Post by ms on Jan 5, 2020 13:17:26 GMT -5
The downshift of the peak with the tone capacitor can justify having a guitar mounted tone control - the interaction of the tone circuit with the pickup is unlike the independently responsive tone controls of the amp. Of course, nowadays an inline equalizer can also do almost anything tonally, if the amp doesn't already cover it. However, that requires a lot of knob twiddling. As the tone volume control resistance decreases when it is turned down, the Q also increases as the resonant frequency drops. It's just serendipity that such a simple circuit also happens to have a sonically useful response. I think it is a very clever circuit, although I suspect the invention was fortuitous rather than purposeful. When the tone pot is turned down partway from 10, the Q drops since the tone C plays no real role at this point except as a short since the magnitude of its impedance at the peak of the (pickup L + cable and pickup C) resonance is small compared to the resistance of the pot
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Post by antigua on Jan 5, 2020 15:15:03 GMT -5
If a resistor (10k maybe) was put in series with the cap, the tone control would act more like a treble roll off, because the resistor would prevent the cap from being wholly in parallel with the pickup, keeping the Q factor down, and it would behave more like the tone control on an amplifier, but apparently guitar makers decided they like the quirky behavior of the tone control as is.
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Post by pablogilberto on Jan 5, 2020 21:52:26 GMT -5
How do we move the resonant frequency of a pickup to around 500Hz to 400Hz? I thought they are usually around 2kHz to 4kHz. Thanks! When you have a tone control set to "0", the cap is fully in parallel with the pickup, and the Q factor is almost fully restored, so essentially you have a pickup with a resonant peak around 500kHz with a 22nF cap, or closer to 400Hz with a 47nF cap, with a Strat style pickup. If the pickup has a higher inductance, like a PAF style humbucker, 22nF caps are often chosen in order to keep the peak closer to 500Hz as much lower than that, it becomes very muddy. You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. It's that lower resonant peak that creates the impression of a humbucker pickup, as the Strat-sized humbucking pickup is physically too thin to actually recreate the tone of a PAF style pickup. They could pretend it was a P-90 if they wanted, but the'59 PAF is beloved by guitarists, so of course they call it that. 1. "When you have a tone control set to "0", the cap is fully in parallel with the pickup, and the Q factor is almost fully restored, so essentially you have a pickup with a resonant peak around 500kHz with a 22nF cap, or closer to 400Hz with a 47nF cap, with a Strat style pickup. " I now get this. But what do you mean with "the Q factor is almost fully restored"? When the pickup is fully in parallel with the cap, the Q factor gets low. Is that what you mean? 2. "You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. " This is interesting and I found it to be true upon doing some circuit analysis. I just noticed that the peak shape becomes steeper / narrow bandwidth. What will be the effect? Also, how do you usually install this cap to be in parallel with the pickup? Directly on the pickup OR in the controls area so you can do a toggle on/off switch maybe? Thanks!
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Post by pablogilberto on Jan 5, 2020 21:59:33 GMT -5
If a resistor (10k maybe) was put in series with the cap, the tone control would act more like a treble roll off, because the resistor would prevent the cap from being wholly in parallel with the pickup, keeping the Q factor down, and it would behave more like the tone control on an amplifier, but apparently guitar makers decided they like the quirky behavior of the tone control as is. Is this similar to a Greasebucket circuit?
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Post by antigua on Jan 6, 2020 2:37:10 GMT -5
If a resistor (10k maybe) was put in series with the cap, the tone control would act more like a treble roll off, because the resistor would prevent the cap from being wholly in parallel with the pickup, keeping the Q factor down, and it would behave more like the tone control on an amplifier, but apparently guitar makers decided they like the quirky behavior of the tone control as is. Is this similar to a Greasebucket circuit? Yes.
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Post by antigua on Jan 6, 2020 3:10:18 GMT -5
When you have a tone control set to "0", the cap is fully in parallel with the pickup, and the Q factor is almost fully restored, so essentially you have a pickup with a resonant peak around 500kHz with a 22nF cap, or closer to 400Hz with a 47nF cap, with a Strat style pickup. If the pickup has a higher inductance, like a PAF style humbucker, 22nF caps are often chosen in order to keep the peak closer to 500Hz as much lower than that, it becomes very muddy. You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. It's that lower resonant peak that creates the impression of a humbucker pickup, as the Strat-sized humbucking pickup is physically too thin to actually recreate the tone of a PAF style pickup. They could pretend it was a P-90 if they wanted, but the'59 PAF is beloved by guitarists, so of course they call it that. 1. "When you have a tone control set to "0", the cap is fully in parallel with the pickup, and the Q factor is almost fully restored, so essentially you have a pickup with a resonant peak around 500kHz with a 22nF cap, or closer to 400Hz with a 47nF cap, with a Strat style pickup. " I now get this. But what do you mean with "the Q factor is almost fully restored"? When the pickup is fully in parallel with the cap, the Q factor gets low. Is that what you mean? 2. "You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. " This is interesting and I found it to be true upon doing some circuit analysis. I just noticed that the peak shape becomes steeper / narrow bandwidth. What will be the effect? Also, how do you usually install this cap to be in parallel with the pickup? Directly on the pickup OR in the controls area so you can do a toggle on/off switch maybe? Thanks! 1) Turning down the tone control gives a series of roll-off profiles that look like this: Once the resistance between the cap and the pickup becomes very low, the Q factor of the RLC circuit becomes high again. It's not as high as it was, because the Q factor calculation is also dependent on the ratio of L and C. 2) A Little '59 has a lower Q factor than a Strat pickup, due to the eddy current losses in the steel parts. The 3nF cap will bring the resonant peak down, but you can also reduce the Q factor of the Strat pickup by rolling the tone control back, or by putting a 100k to 250k ohm resistor in parallel with the pickup. I've done this with push-pull pots on the guitar. You can wire the cap and resistor directly to the pickup, but part of the luxury is being able to do and undo it on the fly. With a push-pull pot the appearance of the guitar isn't even modified at all. The resistor would be in parallel with the capacitor.
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Post by pablogilberto on Jan 6, 2020 21:15:28 GMT -5
1. "When you have a tone control set to "0", the cap is fully in parallel with the pickup, and the Q factor is almost fully restored, so essentially you have a pickup with a resonant peak around 500kHz with a 22nF cap, or closer to 400Hz with a 47nF cap, with a Strat style pickup. " I now get this. But what do you mean with "the Q factor is almost fully restored"? When the pickup is fully in parallel with the cap, the Q factor gets low. Is that what you mean? 2. "You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. " This is interesting and I found it to be true upon doing some circuit analysis. I just noticed that the peak shape becomes steeper / narrow bandwidth. What will be the effect? Also, how do you usually install this cap to be in parallel with the pickup? Directly on the pickup OR in the controls area so you can do a toggle on/off switch maybe? Thanks! 1) Turning down the tone control gives a series of roll-off profiles that look like this: Once the resistance between the cap and the pickup becomes very low, the Q factor of the RLC circuit becomes high again. It's not as high as it was, because the Q factor calculation is also dependent on the ratio of L and C. 2) A Little '59 has a lower Q factor than a Strat pickup, due to the eddy current losses in the steel parts. The 3nF cap will bring the resonant peak down, but you can also reduce the Q factor of the Strat pickup by rolling the tone control back, or by putting a 100k to 250k ohm resistor in parallel with the pickup. I've done this with push-pull pots on the guitar. You can wire the cap and resistor directly to the pickup, but part of the luxury is being able to do and undo it on the fly. With a push-pull pot the appearance of the guitar isn't even modified at all. The resistor would be in parallel with the capacitor. 1. This is clear now. I understand now what you meant. What software did you use for this simulation? I'm looking for something which can vary the potentiometer values during frequency response (AC Analysis). 2. Can you share the frequency response curve of a A Little '59? I want to know the exact resonant frequency values and the quality factor (or just how narrow/wide it is) compared to a typical strat. Visually I mean. That will be helpful. Thank you!
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Post by antigua on Jan 6, 2020 23:23:56 GMT -5
1) Turning down the tone control gives a series of roll-off profiles that look like this: Once the resistance between the cap and the pickup becomes very low, the Q factor of the RLC circuit becomes high again. It's not as high as it was, because the Q factor calculation is also dependent on the ratio of L and C. 2) A Little '59 has a lower Q factor than a Strat pickup, due to the eddy current losses in the steel parts. The 3nF cap will bring the resonant peak down, but you can also reduce the Q factor of the Strat pickup by rolling the tone control back, or by putting a 100k to 250k ohm resistor in parallel with the pickup. I've done this with push-pull pots on the guitar. You can wire the cap and resistor directly to the pickup, but part of the luxury is being able to do and undo it on the fly. With a push-pull pot the appearance of the guitar isn't even modified at all. The resistor would be in parallel with the capacitor. 1. This is clear now. I understand now what you meant. What software did you use for this simulation? I'm looking for something which can vary the potentiometer values during frequency response (AC Analysis). 2. Can you share the frequency response curve of a A Little '59? I want to know the exact resonant frequency values and the quality factor (or just how narrow/wide it is) compared to a typical strat. Visually I mean. That will be helpful. Thank you! 1) I got that from google, but I use LTSPice. I wrote a post about using it to model pickups guitarnuts2.proboards.com/thread/7842/modeling-electric-guitar-ltspice Here's a version of that plot I just made: I have frequency plots of a Little 59 here guitarnuts2.proboards.com/thread/7905/seymour-duncan-little-analysis-review The Q factor is about half that of a Strat pickup. The loaded peak of the bridge is only 1.7kHz, and the neck 2.1kHz, both are rather low, closer to a P-90, not at all like a full sized PAF clone, which tends to range from 2.4kHz to 3.0kHz.
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Post by pablogilberto on Jan 7, 2020 8:58:10 GMT -5
1. This is clear now. I understand now what you meant. What software did you use for this simulation? I'm looking for something which can vary the potentiometer values during frequency response (AC Analysis). 2. Can you share the frequency response curve of a A Little '59? I want to know the exact resonant frequency values and the quality factor (or just how narrow/wide it is) compared to a typical strat. Visually I mean. That will be helpful. Thank you! 1) I got that from google, but I use LTSPice. I wrote a post about using it to model pickups guitarnuts2.proboards.com/thread/7842/modeling-electric-guitar-ltspice Here's a version of that plot I just made: I have frequency plots of a Little 59 here guitarnuts2.proboards.com/thread/7905/seymour-duncan-little-analysis-review The Q factor is about half that of a Strat pickup. The loaded peak of the bridge is only 1.7kHz, and the neck 2.1kHz, both are rather low, closer to a P-90, not at all like a full sized PAF clone, which tends to range from 2.4kHz to 3.0kHz. This is really awesome! Thanks for sharing!
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Post by pablogilberto on Jan 13, 2020 19:55:46 GMT -5
You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. It's that lower resonant peak that creates the impression of a humbucker pickup, as the Strat-sized humbucking pickup is physically too thin to actually recreate the tone of a PAF style pickup. They could pretend it was a P-90 if they wanted, but the'59 PAF is beloved by guitarists, so of course they call it that. Hi antiguaJust wondering. Is this technique similar to doing a mid boost/cut and treble boost/cut for passive guitars? I know that we can not technically get a boost/cut for passive guitars but I'd like to know if we can somehow create a similar effect by changing the resonant frequency, resonant peak and quality factor? Maybe use some R, C or L network? What do you think? Can you share your idea?
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Post by antigua on Jan 13, 2020 21:30:18 GMT -5
You can make a typical Strat pickup sound like a Seymour Duncan Little '59 by putting a 3nF cap across the pickup, bringing the resonant peak to around 2kHz. It's that lower resonant peak that creates the impression of a humbucker pickup, as the Strat-sized humbucking pickup is physically too thin to actually recreate the tone of a PAF style pickup. They could pretend it was a P-90 if they wanted, but the'59 PAF is beloved by guitarists, so of course they call it that. Hi antigua Just wondering. Is this technique similar to doing a mid boost/cut and treble boost/cut for passive guitars? I know that we can not technically get a boost/cut for passive guitars but I'd like to know if we can somehow create a similar effect by changing the resonant frequency, resonant peak and quality factor? Maybe use some R, C or L network? What do you think? Can you share your idea? With a passive RLC network you can change the Q and the peak frequency, and attenuate the low or high end. What I'm describing could be regarded as a mid boost, since you would be moving the resonant peak into the "mid range". What would you want your guitar to do?
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Post by pablogilberto on Jan 14, 2020 8:49:14 GMT -5
Hi antigua Just wondering. Is this technique similar to doing a mid boost/cut and treble boost/cut for passive guitars? I know that we can not technically get a boost/cut for passive guitars but I'd like to know if we can somehow create a similar effect by changing the resonant frequency, resonant peak and quality factor? Maybe use some R, C or L network? What do you think? Can you share your idea? With a passive RLC network you can change the Q and the peak frequency, and attenuate the low or high end. What I'm describing could be regarded as a mid boost, since you would be moving the resonant peak into the "mid range". What would you want your guitar to do? 1. I want to add some switch that will function as a mid boost and mid cut (scoop). Maybe implement using a 2 position mini switch. ie Boost, OFF (no-effect), Cut. 2. I also want to create another version for Treble. ie mid boost and mid cut (scoop). 3. What range of frequencies are talking about when we say, bass, mid and treble in a guitar? Do you also know any article which explain how boosting/cutting a particular range of frequency affects the guitar tone? I'm interested to learn that also.
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Post by antigua on Jan 14, 2020 15:06:46 GMT -5
With a passive RLC network you can change the Q and the peak frequency, and attenuate the low or high end. What I'm describing could be regarded as a mid boost, since you would be moving the resonant peak into the "mid range". What would you want your guitar to do? 1. I want to add some switch that will function as a mid boost and mid cut (scoop). Maybe implement using a 2 position mini switch. ie Boost, OFF (no-effect), Cut. 2. I also want to create another version for Treble. ie mid boost and mid cut (scoop). 3. What range of frequencies are talking about when we say, bass, mid and treble in a guitar? Do you also know any article which explain how boosting/cutting a particular range of frequency affects the guitar tone? I'm interested to learn that also. For a mid boost, I'd put capacitance across the circuit, anything from 3pF to 10pF will create that affect. It's a matter of taste which you choose. For a mid cut, use a "Q Filter" guitarnuts2.proboards.com/thread/8288/bill-lawrence-filter-analysis . If you just use the 2 henry inductor, you get a low end roll off, but if you include the cap and resistor, it works like a mid scoop. The capacitor determines the frequency of the scoop, the resistor determine the depth. The B/M/T frequnecies are arbitrary, but generally guitar amplifiers are configures so that the bass is 1Hz to 300Hz, mids are 300Hz to 800Hz, and treble is everything beyond that.
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Post by pablogilberto on Jan 16, 2020 7:48:37 GMT -5
1. I want to add some switch that will function as a mid boost and mid cut (scoop). Maybe implement using a 2 position mini switch. ie Boost, OFF (no-effect), Cut. 2. I also want to create another version for Treble. ie mid boost and mid cut (scoop). 3. What range of frequencies are talking about when we say, bass, mid and treble in a guitar? Do you also know any article which explain how boosting/cutting a particular range of frequency affects the guitar tone? I'm interested to learn that also. For a mid boost, I'd put capacitance across the circuit, anything from 3pF to 10pF will create that affect. It's a matter of taste which you choose. For a mid cut, use a "Q Filter" guitarnuts2.proboards.com/thread/8288/bill-lawrence-filter-analysis . If you just use the 2 henry inductor, you get a low end roll off, but if you include the cap and resistor, it works like a mid scoop. The capacitor determines the frequency of the scoop, the resistor determine the depth. The B/M/T frequnecies are arbitrary, but generally guitar amplifiers are configures so that the bass is 1Hz to 300Hz, mids are 300Hz to 800Hz, and treble is everything beyond that. Thanks for this! Do you happen to know design principles when it comes to active guitar electronics? I'd like to study them and hopefully build one. I also want to understand why guitars with active pickups or active electronics (on board pre-amps) do not suffer from tone loss due to cables with high capacitance?
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Post by antigua on Jan 18, 2020 1:45:06 GMT -5
For a mid boost, I'd put capacitance across the circuit, anything from 3pF to 10pF will create that affect. It's a matter of taste which you choose. For a mid cut, use a "Q Filter" guitarnuts2.proboards.com/thread/8288/bill-lawrence-filter-analysis . If you just use the 2 henry inductor, you get a low end roll off, but if you include the cap and resistor, it works like a mid scoop. The capacitor determines the frequency of the scoop, the resistor determine the depth. The B/M/T frequnecies are arbitrary, but generally guitar amplifiers are configures so that the bass is 1Hz to 300Hz, mids are 300Hz to 800Hz, and treble is everything beyond that. Thanks for this! Do you happen to know design principles when it comes to active guitar electronics? I'd like to study them and hopefully build one. I also want to understand why guitars with active pickups or active electronics (on board pre-amps) do not suffer from tone loss due to cables with high capacitance? I'm not too familiar with active pickups or on-board signal boosters. I've mostly learned up on matters related to passive pickups, such as magnetism and RLC filters. I know that they're basically using an op amp in it's most basic capacity, which is taking an input signal and outputting it with a greater voltage, with a battery as the power source. For active pickups, this rundown of the EMG81 is very interesting www.electrosmash.com/emg81 Active circuits don't suffer from the effects of cable capacitance because they're low impedance. So long as a guitar cable is involved, the capacitance is always there, presenting an option for current to cross the circuit. If the circuit has a high impedance, then at a high enough frequency, the capacitive connection across the circuit becomes a "path of least resistance" for the high frequency current, and therefore it is taken, and treble content is grounded out. But if the circuit is low impedance, then the circuit itself is the "path of least resistance", even at high frequencies, and so the capacitance never matters.
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Post by pablogilberto on Jan 19, 2020 21:07:46 GMT -5
Active circuits don't suffer from the effects of cable capacitance because they're low impedance. So long as a guitar cable is involved, the capacitance is always there, presenting an option for current to cross the circuit. If the circuit has a high impedance, then at a high enough frequency, the capacitive connection across the circuit becomes a "path of least resistance" for the high frequency current, and therefore it is taken, and treble content is grounded out. But if the circuit is low impedance, then the circuit itself is the "path of least resistance", even at high frequencies, and so the capacitance never matters. Why do passive guitars considered to have high impedance? I know that passsive pickups have DCR or 5k to 15k ohms. Is this high already? The input impedance of an amplifier is around 1Meg I think? Is it because of the electronics involved? (pots values around 250k to 500k). Why do active guitars have low impedance? Can you give me some numbers here or may simple diagrams so I can understand it better.
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Post by antigua on Jan 21, 2020 1:16:55 GMT -5
Active circuits don't suffer from the effects of cable capacitance because they're low impedance. So long as a guitar cable is involved, the capacitance is always there, presenting an option for current to cross the circuit. If the circuit has a high impedance, then at a high enough frequency, the capacitive connection across the circuit becomes a "path of least resistance" for the high frequency current, and therefore it is taken, and treble content is grounded out. But if the circuit is low impedance, then the circuit itself is the "path of least resistance", even at high frequencies, and so the capacitance never matters. Why do passive guitars considered to have high impedance? I know that passsive pickups have DCR or 5k to 15k ohms. Is this high already? The input impedance of an amplifier is around 1Meg I think? Is it because of the electronics involved? (pots values around 250k to 500k). Why do active guitars have low impedance? Can you give me some numbers here or may simple diagrams so I can understand it better. Low impedance is better because, among other things, it's less noisy. The guitar input impedance has to be high, about 1 meg, because the resistance across the output source is divided with (but not "by") the resistance of the input source. A high value of 1 meg makes sure that the very little of the voltage from the guitar pickup is lost. If you load this www.allaboutcircuits.com/tools/parallel-resistance-calculator/ and enter 15,000 for one resistor (pickup) and 1,000,000 for the input resistor, the resistance remains high at 14,778 ohms. But if you put a low value like 15,000 (pickup) and 15,000 (input), the resistance drops to 7,500 ohms, and along with that lower resistance means reduced voltage, and the increased "load" across the pickup means lower Q factor, and the pickup will sound dark. This is why guitars sound so bad when plugged into a low impedance input. The 1 meg input resistor is there to act as a filter. If the value of the input resistor was higher than 1 meg, apparently that can allow more high and low frequency noise to get into the guitar amp, causing you to hear radio stations and other such noise through the amp.
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Post by pablogilberto on Jun 22, 2020 6:10:47 GMT -5
Hi antiguaSince the plain enamel resulted to less capacitance, is it safe to say that it is a better option compared to enameled copper wire? What about formvar? Any thoughts on this? Thank you!
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Post by antigua on Jun 23, 2020 19:14:58 GMT -5
Hi antigua Since the plain enamel resulted to less capacitance, is it safe to say that it is a better option compared to enameled copper wire? What about formvar? Any thoughts on this? Thank you! It could either be build thickness or dieletric value, because I don't know what the dielectric value is. I'm leaning towards build thickness. If I were making pickups, I'd probably seek out wire with the thickest build I could get away with, just for the bragging rights over achieving low capacitance. A difference of 20pF or 40pF it won't affect how the pickup sounds. Guitar cables are typically 40pF per foot, so it's the difference of a foot of guitar cable.
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