Post by antigua on Oct 31, 2020 16:18:57 GMT -5
One mod I've loved for a long time is a "treble" control, running the output through a 1 meg pot with a 1nF to 3nF cap across the lugs (not unlike an ungrounded treble bleed), to roll off the low end.
On another forum, someone was asking about de-mudding an neck humbucker specifically, and I know that a series cap has been used for this purpose. Lately I've had the same problem, I'll jam with a drummer, but without a bass player, so I set the bass kind of high to fill out the low end, and there's a big disparity between the neck and bridge bass output. So I gave it a try, and found that values of 4nF to 10nF trim off a decent amount of low end, 4nF in particular achieves a good parity with the bridge humbucker.
Apparently though, the series cap renders the tone control almost useless, the combination of series and parallel capacitance dramatically lowers the overall output of the pickup. An LTSpice model shows that it actually produces a new resonance of much lower amplitude at a frequency that's lower than the pickup's self resonance, but higher than what you'd get with the tone control alone.
In addition to making the tone control inoperable, it causes the neck pickup to electrically pair differently with the bridge pickup in series, since the neck pickup has a series cap and the bridge doesn't. This model shows that a 4n cap in series with one of two 4H pickups and a typical load produces a notch around 1kHz and a corresponding phase shift. It's not a bad sound though, it gives a mid-range "honk" sort of tone that works good with overdrive and isn't quite like anything I've heard with other wiring layouts. And of course, the neck pickup by itself has a tighter low end without losing the higher harmonics of the wound strings.
Because it's such a big tonal difference when the neck and bridge are selected together, I've decided that it's not a good permanent modification to make, but it's a killer push-pull option. My HH guitars are generally 2 vol 2 tone, which leaves a lot of room for push pull pots. The neck tone control is a logical place for a push-pull that puts a cap in series with the pickup. I'm planning to mod a few more of my HH's this way.
There actually was a discussion about the effects of neck series caps here about 10 years ago guitarnuts2.proboards.com/thread/5176/half-out-phase , and they discussed using the cap in conjunction with a control, but I think, in contrast to that discussion, a simple push pull to enable or disable the effect is very usable.
A parallel inductor can have the effect of rolling the bass off without affecting how the tone control works, and for the purposes of a hard wired bass attenuation, that might work better, but the use of a series cap has some unexpected upsides. Inductors are also more expensive, and you often have to make them yourself in order to get the desired spec points. Someone might make a two pole Gibson style pickup selector, which could bypass the series cap in the middle position, and then the series cap could be placed on the other side of the tone control, and that would solve the issue too, but I really like having access to that in between position sound with the cap still in series.
On another forum, someone was asking about de-mudding an neck humbucker specifically, and I know that a series cap has been used for this purpose. Lately I've had the same problem, I'll jam with a drummer, but without a bass player, so I set the bass kind of high to fill out the low end, and there's a big disparity between the neck and bridge bass output. So I gave it a try, and found that values of 4nF to 10nF trim off a decent amount of low end, 4nF in particular achieves a good parity with the bridge humbucker.
Apparently though, the series cap renders the tone control almost useless, the combination of series and parallel capacitance dramatically lowers the overall output of the pickup. An LTSpice model shows that it actually produces a new resonance of much lower amplitude at a frequency that's lower than the pickup's self resonance, but higher than what you'd get with the tone control alone.
In addition to making the tone control inoperable, it causes the neck pickup to electrically pair differently with the bridge pickup in series, since the neck pickup has a series cap and the bridge doesn't. This model shows that a 4n cap in series with one of two 4H pickups and a typical load produces a notch around 1kHz and a corresponding phase shift. It's not a bad sound though, it gives a mid-range "honk" sort of tone that works good with overdrive and isn't quite like anything I've heard with other wiring layouts. And of course, the neck pickup by itself has a tighter low end without losing the higher harmonics of the wound strings.
Because it's such a big tonal difference when the neck and bridge are selected together, I've decided that it's not a good permanent modification to make, but it's a killer push-pull option. My HH guitars are generally 2 vol 2 tone, which leaves a lot of room for push pull pots. The neck tone control is a logical place for a push-pull that puts a cap in series with the pickup. I'm planning to mod a few more of my HH's this way.
There actually was a discussion about the effects of neck series caps here about 10 years ago guitarnuts2.proboards.com/thread/5176/half-out-phase , and they discussed using the cap in conjunction with a control, but I think, in contrast to that discussion, a simple push pull to enable or disable the effect is very usable.
A parallel inductor can have the effect of rolling the bass off without affecting how the tone control works, and for the purposes of a hard wired bass attenuation, that might work better, but the use of a series cap has some unexpected upsides. Inductors are also more expensive, and you often have to make them yourself in order to get the desired spec points. Someone might make a two pole Gibson style pickup selector, which could bypass the series cap in the middle position, and then the series cap could be placed on the other side of the tone control, and that would solve the issue too, but I really like having access to that in between position sound with the cap still in series.
