Pot Values

[Tenderfoot]

You would not think it would be a big deal, but a simple volume pot change from 500k to 250k not only knocked off just the right amount of highs but also seemed to balance the freq. from string to string

[julkke]

I found that with humbuckers the sound got a bit too muffled with 250k pot. Glad it works for you!

[Tenderfoot]

Yeah, I put a Lace Sensor dually in the bridge and love it. I guess I'm just a single coil type of guy!

[JimiJames]

Me likey 300k audio taper.

250k/300k linear for Tone(s) w/.05
33°F Stella's in chilled glass

[Tenderfoot]

The Lace sensors seem to have a wide field. Even though they say the nickel and two dime method for height adjustment I have mine closer.I only have tone on the neck, 500k linear with a Wilde eq. I wouldn't mind trying 300k on the volume, but I've only seen them in linear not audio.

[julkke]

I gotta try a 300k now too. Right now my strat has 500k pot (measures 463k) and a 470k resistor from neck single coil hot to ground, making the single see close to 250k. 300k might be bit more dark but not muffled, especially if I found one which reads a little high.

[demonufo]

Yamaha do a beautiful quality 330K Log taper pot. The one's I have are a push/push switching pot though, and are now wickedly expensive. The price has jumped up quite considerably over the years. Well worth trying to source some though.

[fillmore nyc]

I've been playing around with pot values a LOT lately (on a Fender Esquire... one pickup) and have learned quite a bit in the process.

Whatever value you're using on the volume pot (which ideally should be audio taper) is giving you more or less punch and upper frequency response TO A POINT, depending on the pot value.

Whatever you're using on the tone control (ideally, linear taper) is more of a determining factor as to the upper frequency response, since the signal goes thru a cap before ground, and wont turn the guitars volume off to any appreciable degree.

On the Esquire I've been screwing around with, Im using a Duncan Custom Shop BG-1400 (http://www.seymourduncan.com/products/c ... 2930k_for/" onclick="window.open(this.href);return false;) and the circuit is whats known as the "Eldred", or "cocked wah pedal" mod, but I've gone WAY out of the box with the traditional Eldred, to what could now be called a "Filldred" mod... (or an Elmore mod??)

In simple terms, with the single pickup in an Esquire, the Eldred still has the single volume, single tone pot arrangement and the 3 way switch which operates as follows:
Position 1 (rearwards): Normal control operation... volume and tone pots working as normal.
Position 2 (middle): Tone control (and the load it presents on the circuit) is disabled completely... pickup "sees" the volume pot only (resulting in a hotter sound)
Position 3 (forwards): Volume pot only (tone pot is still disabled), but the signal is routed thru a small value cap, giving the aforementioned "cocked wah pedal" tone.

The traditional Eldred uses a pair of 250k pots, a .047uF cap for the tone pot, and a .01uF cap for the 3rd position "wah" tone.
IMO, those values didnt work well at all... the tone circuit (using any cap approaching .05uF) is useless... it sounds like a pillow is stuffed into the amps speakers. WAY too muddy and unusable. Same can be said for the .01uF for the 3rd position... it vaguely sounded like it was supposed to, but it was also much too muddy.
I didnt like how the pot values were affecting the sound either. The BG-1400 is a STUDLY bastard of a pickup with lots of everything... bottom, mids, top and output. With 250k pots, it sounded a bit "soft" and weaker than it should have, and the volt meter revealed that... wired directly to the meter, the pickup read 29.8k. In the guitar it read 26.2k

So, time to bring it to the lab.
First thing was swapping out the caps. It now has a .003uF Aerovox paper in oil cap for the tone pot, and a .0022uF Midwec cap for the 3rd position. (Thats not a typo... they ARE .003uF and .0022uF caps, NOT .03uF and .022uF)
MUCH better results tone wise. The tone pot itself is MUCH better sounding, especially with any gain in the amp, and the "cocked wah" position sounds awesome... but the guitar still sounded a bit anemic output wise, and since the pots werent changed (yet) it still read 26.2k on the meter.

Next up was the volume pot... swapped it out for a 500k, and left the 250k for the tone pot.
Much better overall punch, a more noticeable difference in ALL switch position, especially the 2nd position (volume pot only).
Guitar now reads 27.3k on the volt meter.

I wanted to see how far I could take this, and still retain a musical, usable tone, so... back to the lab.
Changed the volume pot (again) to a 1meg, and at the same time, added a bright cap mod, consisting of a NOS .0015uF Sprague Orange Pacer cap, and a 150k resistor, wired in parallel, across the middle and hot leg of the volume pot... same 250k tone pot.

WINNA!! Guitar has a TON of balls and output, and sounds amazing. It now reads 28.5k on the meter. The diff between position 1 and 2 is even more noticable, and all positions sound awesome.
Im sure it would sound too bright if I used anymore than a 250k for the tone pot, and as a last mod, I "might" just try a 100k tone pot, which would retain the output, and tame the highs a bit more, but it doesnt NEED it... its just my obsessive nature to TRY it.
The majority of this post is referring to what occurred with the change made to the volume, tone pots and tone cap... Im just mentioning the Eldred mod (and what happened in positions 2 and 3) to present the whole picture.

SO... relating this to a pickup with a dedicated volume and tone control, it seems (to me, at least) that its unnecessary to use a large value cap in the tone circuit, simply for its effect when the tone control is unused (on "10").
Also, going with something like a 250k on the volume pot seems to rob the guitar of a lot of its potential as far as punch, output and frequency response.
The idea of using a purposely mismatched volume and tone pot value, and using a smaller value cap just seems to work way better than the traditional method of a pair of 250k pots and a cap between .022uF and .05uF, at least in the guitar mentioned above. The lower resistance pot, and a small value cap (.003uF to .005uF) in the tone circuit still allows some highs to be shaved off, and sounds MUCH more usable when the tone pot is actually used.
Im interested to see how this works with a PAF style humbucker guitar, which is the next project.

Anyway, this is what I've found lately regarding the interaction between pickup output, volume pot value, tone pot value, and the tone cap value.

BTW, if anyone wants a diagram of the "Eldred" (or "Filldred") mod, lemme know and Ill post it. It would work with any single pickup guitar that has a volume, tone and a Fender 3 way switch.