Changing Resonant Frequency instead of Changing Pickups

WKSmith said:
This is an awesome mod.

Resistance in parallel does change the pots taper though.

This is exactly why I use 250k pots on my P90s. It corrects a nasty spike from the filter corner frequency created from the pickups inductance with the pots resistance.

Some folks use 300k pots or 330k like this cheap one

https://www.guitarfetish.com/XGP-Cu...30K-P90-Overwound-Tone-Our-Best-_p_22991.html
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Thanks! I had read about the taper change, but honestly, I didn't notice any negative impact in riding my knobs and getting what I want right away. I put off doing this for like a month because of the assumption that the taper change might suck; at least for my purposes, it didn't at all. I think I read that if you go between lugs 1 and 2 it doesn't affect the taper, but I'd have to find the source on that. I asked the Bing chatbot about that, and it gave a wishy washy answer from a forum post, so it would be something to experiment with. The pots you linked are interesting too, since they're linear and not log.
 
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scottp said:
Wow, this is a crazy neat idea. Can't wait to hear/see more!
I really like the idea of the small trim pots. You can always make an adjustment if needed.
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About the extra adjustment if needed, I realized that when I had my Floyd off, I accidentally lowered the action a wee bitty hair, and that of course affected the tone before my sweetening. So I'm going to raise the action a little bit then see if I need to readjust the trimpots to sweeten again; I imagine I'll need to reduce the sweet to add back a hair more clarity after raising the action. The guitar plays great with low action, but really low action just never sounds as good to me; I never measure; I just raise it a hair until it feels and sounds right. I'm also thinking about making a big change to a new pick. I keep a cache of various picks around that I whip out every couple of years or so, and I decided to whip it out yesterday. I was shocked to find that the one Fender 351 Heavy pick I had in that huge array may have been the best sounding one to my ears, compared to my Dunlop Tortex Standard .60 that I've used for a while. That Fender just had a great attack that I loved last night, but I don't know if it's one of those picks that only sound good when a little worn, so I bought a 12 pack of them last night, and I'll compare fresh Tortex with fresh 351s. Once I make a decision on the pick too, I'll adjust the sweetening to fit it, and I'll be set.

That's the other thing about being able to tune resonant frequency by ear on the fly, pick attack will change greatly with the pick you try. So maybe you find a pick that's really comfortable, but it sounds like dogshit. Well, maybe if you retune the resonant frequency of your pickups, all of a sudden that pick may sound great with your guitar. In fact, that makes me want to try tuning the resonant frequency to the Dunlop Jazz III 1.14 that I have. That thing really lets my wrist loosen and fly, so maybe I oughtta just try tuning to that pick first. See, I'm just thinking out loud here! This has opened a whole can of worms to me. It makes me feel like, with any passive system, you can just take a guitar, a model / gauge of strings, a pickup, or a pick that feels great but maybe didn't have the tonal mojo you wanted, and with the right tuning, if your pickups are close enough stock, you can get the mojo out of them.

I mean I didn't even take a second to balance the pole pieces, as I had done on my most recent pickups. I can imagine that will only further perfect the output.

One thing also to keep in mind: I found that as I was sweetening, I was able really to hear more finely if the pickups needed to be raised or lowered to match each other's output, so I was playing with that at the same time. And I forgot that you're using these same pickups Scott, the Saturday Night Specials. I feel like, if I could get them to sound good in this bright guitar, they truly can sound great in anything, with the right tuning.

This is also the kind of thing I can see, in a more nuanced way, curing the hatred of those of us who found, e.g., a Duncan JB to be a shrill hatefist. This could also be the ultimate tool to balance and HSS set. Man, for an HSS, you could have one trimpot in parallel, as I've described, to sweeten the resonant frequency, then another in series, between the humbucker's hot and the volume knob, to lower it's output to match the single coils. It's so the idea of taking what is unchangable, the resonance of the wood of the guitar and its construction, and tuning the pickups to be as receptive to the pleasing resonances in that guitar as possible. I just keep thinking that maybe this would keep you from having to get rid of a guitar that sounds terrible but feels great. Because I really feel like my guitar, without the sweetening, really took way too much processing to sound good. Now that's not a problem at all. It's just sitting right with all the amps I've tried so far.
 
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This is a cool mod. I think this is basically what PRS is doing with the TCI process. They are setting the resistance to specific levels. I am not sure how they are measuring that or what they are looking for but I believe they are basically doing this same thing. I am also not sure if they are using any sort of adjustable resistance or if they measure things and then solder in static value components. I don't own any of the newer TCI tuned PRS guitars to look in the control cavity fo find out.
 
JasonE said:
This is a cool mod. I think this is basically what PRS is doing with the TCI process. They are setting the resistance to specific levels. I am not sure how they are measuring that or what they are looking for but I believe they are basically doing this same thing. I am also not sure if they are using any sort of adjustable resistance or if they measure things and then solder in static value components. I don't own any of the newer TCI tuned PRS guitars to look in the control cavity fo find out.
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Oh cool! I'll have to read about that now...
 
JasonE said:
This is a cool mod. I think this is basically what PRS is doing with the TCI process. They are setting the resistance to specific levels. I am not sure how they are measuring that or what they are looking for but I believe they are basically doing this same thing. I am also not sure if they are using any sort of adjustable resistance or if they measure things and then solder in static value components. I don't own any of the newer TCI tuned PRS guitars to look in the control cavity fo find out.
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Okay, that is really interesting. I guess if you know for sure that the resonance of that Core series guitar body is always the same, and that each particular one will definitely resonate well with the particular pickup resonance they're targeting. I think it would be awesome if it really was a process done by ear, because I just imagine that, even within the same series of guitars, like two made from the same tree even, that the body resonances would be different. But I think you're right; these guys are tuning the pickups to the model of guitar, at least, to reach a target frequency curve they've predefined. And I guess the difference is that I was just going entirely by ear! So cool to know this is in production model stuff! And I'm really curious not so much if it sounds good, because I'll be it sounds great, but if it more or less consistently sounds good in every guitar they produce in that line, if my assumption that variances in wood would make the process moot is just wrong.
 
I'm also thinking one might want to retune the resonant frequency of your pickups when changing cables too. Since a change in instrument cable is another factor that changes the LCR network. One could I guess even do that when plugging into a fuzz pedal to fine tune the response, since that's more perceptibly a function of the pedal's input impedance and its resulting load on the pickups.
 
I still haven't been able to finish, because life got in the way, but it did occur to me that it's probably best to ground lug 1 of the trimpots too, in case anyway else plays around with this. I didn't hear a problem in my testing, but maybe it would be a problem in a different environment.
 
Kamil Kisiel said:
Those things are generally pretty big though :) That's why a rotary switch with some fixed values is more common.
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nothing a router can't fix but sure it is relatively bigger compared to your potentiometers.

just suggested since OP seems to like to sweep through a range of frequencies and not at fixed intervals

I've just basic knowledge of electronics so pardon me
 
Kamil Kisiel said:
This is a really cool idea. I could see making a small PCB that could be installed in a guitar with these types of controls. Have you seen this idea with a rotary switch for selecting different capacitors? http://www.buildyourguitar.com/resources/lemme/
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Thanks so much! Coincidentally, the trimpots I ordered are designed to be mounted to breadboards. I've been thinking the ultimate way to do this would be to have these mounted in a compartment on the back of the guitar with a door you could open, maybe the size of a battery box door, to do your tweaking; you could totally have a PCB for that purpose; though, like all PCB onboard stuff for guitar, the dangers are rejection by players for being non traditional, and the lack of ready availability of replacement PCBs if something goes wrong; if you just use trimpots, you can get those a million places online, and they cost nothing.

I have read that article, and I love the idea of the switchable caps, which I've also seen in posts on several different forums. Talk about fine tuning! But from my understanding you only use a cap if you want to raise the resonant frequency. In that case my first thought would be to use alligator clips to audition values, choose one that's close enough but makes the guitar too bright, then use a trimpot to bring it down to where it's perfect. I could be wrong on this being the best way, but it seems like an easy and cost effective way to do it.
 
ApocalypticKatana said:
Found this and I think it would be relevant to what you want to do
View attachment 117750
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Yes, thanks for posting that! I have researched variable caps before, but they did seem impractical to me just because of the size. It would be ideal to combined variable caps with variable resistors for quick and precise tweaking, but variable caps also kind of look to me like more could go wrong. Since a fixed cap is so cheap and readily available, I'd more inclined to do what I mentioned above: go a little too bright with a fixed cap, then fine tune it to the sweet spot with a trimpot.
 
State of Epicicity said:
Thanks so much! Coincidentally, the trimpots I ordered are designed to be mounted to breadboards. I've been thinking the ultimate way to do this would be to have these mounted in a compartment on the back of the guitar with a door you could open, maybe the size of a battery box door, to do your tweaking; you could totally have a PCB for that purpose; though, like all PCB onboard stuff for guitar, the dangers are rejection by players for being non traditional, and the lack of ready availability of replacement PCBs if something goes wrong; if you just use trimpots, you can get those a million places online, and they cost nothing.

I have read that article, and I love the idea of the switchable caps, which I've also seen in posts on several different forums. Talk about fine tuning! But from my understanding you only use a cap if you want to raise the resonant frequency. In that case my first thought would be to use alligator clips to audition values, choose one that's close enough but makes the guitar too bright, then use a trimpot to bring it down to where it's perfect. I could be wrong on this being the best way, but it seems like an easy and cost effective way to do it.
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PCBs cost almost nothing to manufacture these days and it’s a lot easier to wire something more complex up on one. I don’t think you need to worry about “traditional” with a system like this heh.

Seems like a fun project, I’d be interested in doing up a design for it
 
Kamil Kisiel said:
PCBs cost almost nothing to manufacture these days and it’s a lot easier to wire something more complex up on one. I don’t think you need to worry about “traditional” with a system like this heh.

Seems like a fun project, I’d be interested in doing up a design for it
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Very cool. If you ever created a board like this, I'd be on it! You're right too, that anyone interested in a PCB pickup resonance adjustment wouldn't be worrying about traditionalism. I guess on a PCB you could design it to have several selectable cap values, including none (if you only wanted to lower resonance), then also have a trimpot built in, maybe even at a switchable value, like 250, 500, or 1000k. Maybe that's not necessary, but I guess there would be many ways to do it, and it could be tiny.
 
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