Capacitance P90 mount and high frequencies

[RockinProf]

Hey again all,

This is a super nuanced question that might not have an available answer, but I'll ask anyways. I have a new SG special that is just fantastic, the weight, feel and acoustic tone are just what I wanted. The 60hz hum was unbearable though. After doing the appropriate reading on the appropriate pickups to give the exact P90 vibe but kill the hum I landed on the MojoTone Quiet Col 56 set. These are really authentic in all ways. The interaction between the volume knob and the gain that you're feeding in to is dead on, the mids and bass are right there with a Gibson P90, the high sparkle is 90% of the way there... but it seems a little subdued. Yes I'm being ultra critical and the removal of the crazy him makes the guitar usable with gain where it wasn't one that I'd take out as the noise was just too extreme (even after a very comprehensive shielding job that was checked with a meter across all surfaces.

With those considerations I came to think that the way that the pickups are mounted is with a large metal plate that set screws fit in to - as equipped by Gibson. Is it reasonable to believe that these mounts create an audible level of capacitance that would shunt some of the high frequencies that I'm observing as being attenuated? MojoTone did provide wood screws that would allow for the mounting to the wood if the metal mounts were removed. Thoughts on if this would warrant anything audible or would this be so small of a difference that it would be imperceptible?

If there's theoretical validity I'll remove the plates on the next string change.

Thanks

RP

[Chistopher]

Try it, the amount of confirmation bias on the internet for little things like this is only going to make you disappointed if your perception of events doesn't line up with how the goobers on the internet say you should perceive them.

[freefrog]

It's a question of Foucault currents (eddy currents) more than of capacitance, in my understanding...

I can't tell if removing the baseplates would make a difference in this case, though: I've never tried the Mojotone's but I know for a fact that most noise-cancelling single coil substitutes are more or less affected inherently by the dulling effect of eddy currents. That's why Chris Kinman did design a P90Hx with a noise cancelling bobbin wound around a laminated core, like those of transformers... So, not sure that removing some metal baseplates would solve the issue with other designs. But who knows? it doesn't harm to try...

HTH. Good luck in your tone quest.

[RockinProf]

It's a question of Foucault currents (eddy currents) more than of capacitance, in my understanding...

I can't tell if removing the baseplates would make a difference in this case, though: I've never tried the Mojotone's but I know for a fact that most noise-cancelling single coil substitutes are more or less affected inherently by the dulling effect of eddy currents. That's why Chris Kinman did design a P90Hx with a noise cancelling bobbin wound around a laminated core, like those of transformers... So, not sure that removing some metal baseplates would solve the issue with other designs. But who knows? it doesn't harm to try...

HTH. Good luck in your tone quest.

I might as well give it a shot on the next string change, the effort is minimal. The MojoTone quiet coils are a really novel way to do hum cancelling. They take thin bobbins and place the magnet in the coil firebird style and rotate them 90 degrees. The poles are between the magnet imbedded bobbins. If that's good/bad. better/worse than Kinman's spin or any other design is in the ear of the beholder. I'm very impressed on how well the tone is extremely similar across the majority of the frequency curve. It is entirely possible that the inherent nature of hum cancellation does interfere with high frequency representation... Granted there may be other variables at play, as I did restring as I changed the pickups and went from the Gibson strings that were equipped to D'adario XS strings. I've found the XS line to be rather unaffected with the coating compared to other strings, but it is a difference .... that is amplified thousands of times the original value, so that can't be ruled out. The metal bracket does seem like a place where a lot of capacitance could hide.... so I guess I'll see what happens when I alter that variable.

[GuitarStv]

There's always going to be a little cancellation of higher frequencies when you make a single coil design noiseless by adding another coil. Modern designs are good, but I can hear the loss in the highest frequencies with single coil designs. I'm guessing that this is what you're hearing. You might get a little more highs back by messing around with the mount, and it's worth trying but my suspicion is that you're hearing the noise cancelling design.

[freefrog]

I might as well give it a shot on the next string change, the effort is minimal. The MojoTone quiet coils are a really novel way to do hum cancelling. They take thin bobbins and place the magnet in the coil firebird style and rotate them 90 degrees. The poles are between the magnet imbedded bobbins. If that's good/bad. better/worse than Kinman's spin or any other design is in the ear of the beholder. I'm very impressed on how well the tone is extremely similar across the majority of the frequency curve. It is entirely possible that the inherent nature of hum cancellation does interfere with high frequency representation... Granted there may be other variables at play, as I did restring as I changed the pickups and went from the Gibson strings that were equipped to D'adario XS strings. I've found the XS line to be rather unaffected with the coating compared to other strings, but it is a difference .... that is amplified thousands of times the original value, so that can't be ruled out. The metal bracket does seem like a place where a lot of capacitance could hide.... so I guess I'll see what happens when I alter that variable.

I've never tried the Quiet Coils but I did vaguely remember how they're made. To me, that's a variation on an old design, named "sidewinder" and previously materialized by pickups like the Gibson EB3 bass PU. Some more recent Firebird pickups are also like that, if memory serves me.
Regarding capacitance: it's a factor that I've permanently in my mind although it's often overlooked and I measure it each time it's possible... but IME, solid pieces of metal are not that capacitive, whatever are their dimensions and mass: a few dozens of picofarads, at best. Not enough to dull the tone. Parasitic capacitance of coils and/or wiring is a whole other story IME / IMHO.

Anyway: I wasn't evoking Kinman to compare his products to MojoTone ones. It was just an example meant to illustrate my rambling about Foucault currents. If you're happy with your Quiet Coils, I've no reason to recommend you something else: I'm just glad for you...

Let us know if removing the metal brackets makes a difference. I'll read your conclusions with interest. :-)

[RockinProf]

I've never tried the Quiet Coils but I did vaguely remember how they're made. To me, that's a variation on an old design, named "sidewinder" and previously materialized by pickups like the Gibson EB3 bass PU. Some more recent Firebird pickups are also like that, if memory serves me.
Regarding capacitance: it's a factor that I've permanently in my mind although it's often overlooked and I measure it each time it's possible... but IME, solid pieces of metal are not that capacitive, whatever are their dimensions and mass: a few dozens of picofarads, at best. Not enough to dull the tone. Parasitic capacitance of coils and/or wiring is a whole other story IME / IMHO.

Anyway: I wasn't evoking Kinman to compare his products to MojoTone ones. It was just an example meant to illustrate my rambling about Foucault currents. If you're happy with your Quiet Coils, I've no reason to recommend you something else: I'm just glad for you...

Let us know if removing the metal brackets makes a difference. I'll read your conclusions with interest. :-)

So I gave it a shot, kept the same strings for a control over the variables. The difference was…. absolutely nothing that I could perceive from dead clean with a Deluxe Reverb to filthy as politics with a boosted JCM 800. For fun I lifted the signal from the volume pots to the tone pots - To quote Tag Team - Whoop There It Is. I do have 500K pots but it seems like they were passing too much treble to ground (note the pots in this read from 480K to 510K. I’m sure I have some no-load pots around. I’ll swap those fir the tone controls. Mystery solved.

[RockinProf]

There's always going to be a little cancellation of higher frequencies when you make a single coil design noiseless by adding another coil. Modern designs are good, but I can hear the loss in the highest frequencies with single coil designs. I'm guessing that this is what you're hearing. You might get a little more highs back by messing around with the mount, and it's worth trying but my suspicion is that you're hearing the noise cancelling design.

You are right. I lifted the lead to the pots and things sounded right immediately. The humbucking clearly attenuates highs. Disallowing the highs that are there to pass to ground worked. The guitar sounds fantastic.

[Chistopher]

No load pots work okay, but first I would say replace your current 500k pots with 1 meg pots of the same taper. It will brighter your tone up by the exact same amount as a no-load tone control, but you won't have the jump in brightness and volume at 10 that a no-load has

[freefrog]

So I gave it a shot, kept the same strings for a control over the variables. The difference was…. absolutely nothing that I could perceive from dead clean with a Deluxe Reverb to filthy as politics with a boosted JCM 800. For fun I lifted the signal from the volume pots to the tone pots - To quote Tag Team - Whoop There It Is. I do have 500K pots but it seems like they were passing too much treble to ground (note the pots in this read from 480K to 510K. I’m sure I have some no-load pots around. I’ll swap those fir the tone controls. Mystery solved.

Not surprised by the results. Recommending some 1M or no-load tone control(s) would have been my next advice anyway. ;-)

Ironically, how Kinman voices his noiseless P90Hx requires the opposite strategy: 250k instead of 500k pots, or the resonant peak is a wee bit too prominent...

Shows once again the importance of wiring. Enjoy with your Quiet Coils!

[RockinProf]

No load pots work okay, but first I would say replace your current 500k pots with 1 meg pots of the same taper. It will brighter your tone up by the exact same amount as a no-load tone control, but you won't have the jump in brightness and volume at 10 that a no-load has

Well I tried the lazy version of your suggestion and used a little mist of DeOx-It D5 in the opening for the lugs on the pots and seasoned the pots to taste. I found that "cleaning" the carbon to ~700K to 800K got me to just the right place. I guess the moral of the story is that - as with most things - la little bit of time with (what ever you're working with) and trying new things as you're getting used to it lead to the best results. I'm willing to bet there are scores of people out there with a cupboard full of great pickups that installed and set to a value on a ruler.... when they weren't ideal upon setup after a week or so they go replaced again. My teaching moment from this is that if a pickup isn't dead on out of the box, fool with it a bit, you might just need to dial it in for your specific instrument.

Thanks all.

[gimmieinfo]

I have yet to hear any noiseless pickup meany to be a noise free single that DIDN'T compromise the top end causing duller trebles. Even shielding a guitar if done well enough to eliminate much of the noise will take the top end with it. A NON noiseless real P90 is plenty bright which pretty much should eliminate the possibility the plate is causing your problem. If it were then real P90s would sound like that too. Far as i know, no one has successfully designed a noiseless pickup thats 100% the same. It;s a different design so it likely never will be. It's just a matter of which players can tell and which can't.

[RockinProf]

I have yet to hear any noiseless pickup meany to be a noise free single that DIDN'T compromise the top end causing duller trebles. Even shielding a guitar if done well enough to eliminate much of the noise will take the top end with it. A NON noiseless real P90 is plenty bright which pretty much should eliminate the possibility the plate is causing your problem. If it were then real P90s would sound like that too. Far as i know, no one has successfully designed a noiseless pickup thats 100% the same. It;s a different design so it likely never will be. It's just a matter of which players can tell and which can't.

I agree that the characteristics of noise deterrence will inherently influence the observable traits of a pickup's sound. At the same time, some noise cancellation techniques and technologies are much better than others. Case in point being ng the Dimarzio HS-2. Some have found ways to get really good sounds out of these..... not traditional strat single coil tones though. At the same time, the Dimarzio Area 58 pickups (under the condition that the values on the pots are 500K+) are indistinguishable from a real single coil strat pickup in a band mix. No the Area 58 isn't dead on across all observable frequencies and nuances, but really close. In the case of this MojoTone Quiet Coil 56, it actually does an exceptionally good job at getting the P90 sound right. The capacitance theory was a red herring, but like the Area Dimarzio pickups, preventing the high frequencies that were not cancelled in noise deference was critical in getting them to sound right. Again, if one were to listen very critically in an isolated environment, and had an ear trained for subtle frequency an nuance deviance they would hear the difference between the MojoTone and a "real" 1956 P90. That is just a fact. On the other hand, if the MojoTone is setup correctly(with respect to height) and with the pots tuned to the system that is the guitar, I strongly doubt that even a trained listener could hear a difference between the MojoTone and the "real" 1956 P90 in a band mix if they were not observing tonal differences rather than listening to the music.

With all of this considered and knowing the Seymour Duncan as a company does use information discussed here to design new products- Mercer77 I don't think anyone would be offended if you brought forward the idea of a tuneable potentiometer. Having the ability to increase or decrease the resistance of a potentiometer is a great idea that no one has implemented yet. Yes there would be engineering required, but the idea of a potentiometer or a group of potentiometers that start at 250K as a floor value and have resistance that scale up to perhaps 1 Meg via an attached sub pot is an excellent idea. Yes it s niche and the device would need to accommodate for taper as the resistance of the pot is changed. If this can me done.... well shut up and take my money