Question about a more advanced treble blled idea

[daz]

Heres the deal...i found i really lie a 1000pf with a 220k in series as a TB. The 220k cuts the effect of it down to where it's just right. But i have also used a 250pf with no resistor and what i liked about that i miss with the 1000pf/220k. The latter gives me a nice clarity in a keith richards sorta way, and i realize the 1000pf passes the same frequencies as the 250pf, albeit MORE in lower ranges too. But the sparkle at the very top that i got with the 250pf is subdued in the 1000pf because of the resistor. So the question is, what would happen if i paralleled a 250pf with the 1000pf and 200k that are in series ? Yes, i can try it and i will, but B4 i do i wanted to know what theoretical considerations there might be so i am more informed as to what to expect. You all usually point to charts and formulas etc when someone asks a question like this, so thats what i'm looking for. More laymans terms as to what ill happen rather than math tho, as that goes whooosh. What i'm really trying to find out here is whether this idea will do exactly what i want which is give me that sparkle the 250k had on top of the attenuated range of treble the 1000pf affords so that i'd get that sound i had with the 1000pf/220k AND the sparkle of the 250pf on top of it without any weirdness that might occur due to theoretical things i'm not aware of. I likely will also use a resistor in series with the 250pf to get the right amount of that sparkle too. Should this work or no?

[pdf64]

If you create an account at Best custom noiseless guitar pickups with zero hum by Kinman.com then he has a procedure under the 'perfect guitar' tab regarding this idea and how to select suitable component values.

[daz]

If you create an account at Best custom noiseless guitar pickups with zero hum by Kinman.com then he has a procedure under the 'perfect guitar' tab regarding this idea and how to select suitable component values.

I have no problem with values. I know exactly what i want in that regard, I just want to know whether my Idea will work as I intend It to.

[Steve A.]

Treble bleed circuits reflect personal tastes; charts and formulae would be of no use unless you knew all of the specs of the pickup(s). If you like both of the circuits you mentioned you might want to install a push-pull pot so that you could toggle between the two.

If you want to experiment I suggest that you get two trim pots and try to dial in sounds that you like. (For a strat-like guitar with no rear panel access I would remove a pot and run the wire through that hole.)

FWIW I usually move the cap or jumper going to the tone control from terminal #3 to the wiper (called 50's wiring by many) and don't feel the need for a treble bleed cap or RC network on volume pots, which can give you unnatural sounds, the classic example being the .001uf treble bleed cap on a tele. Full up you can get a great lead sound from the bridge pickup with a lot of mids but as you turn the pot down the sound gets cleaner and brighter.

Steve Ahola

[Mark Hammer]

My own gut sense is that the cap-only path will effectively trump the cap+resistor path, simply because the only impedance there is provided by the cap itself.

I could see running a larger-value cap with a resistor, to introduce/pass a bit of content slightly below what the cap-only path provides. But, if you'll pardon me ascribing motives to electronic signals, why would the signal "want" to go through the RC path when it could simply go through the C-only path?

[Steve A.]

My own gut sense is that the cap-only path will effectively trump the cap+resistor path, simply because the only impedance there is provided by the cap itself.

I could see running a larger-value cap with a resistor, to introduce/pass a bit of content slightly below what the cap-only path provides. But, if you'll pardon me ascribing motives to electronic signals, why would the signal "want" to go through the RC path when it could simply go through the C-only path?

In my experience the resistor "tempers" the effect of the capacitor to mellow it out a bit... PRS usually uses an 180pF ceramic cap with no resistor. If you were to use a larger capacitor like 680pF you would probably want to add a resistor to lessen the effect.

Another way of looking at is that a resistor with or without a capacitor from the hot terminal to the wiper would make the an audio taper more linear (and a linear taper more like reverse audio.)

Steve

P.S. The signal is going to go through an RC path with or without an added resistor since the pot itself provides the resistance.

[Chuck H]

The 1000p in series with the 220k, then paralleled with a 220p, probably won't give you the nirvana you hope for. The reason is that what you actually want is the sparkle of the 220k only AND the mud abatement and mid bump from the 1000p/220k only. It doesn't work like that. Two different tones. When you mix the circuits you get a sum/difference of both simultaneously and it just doesn't sound the same. That doesn't mean you can't find a combo that will get damn close. You probably can! Maybe a 680p in series with a 330k all paralleled with a 100p cap.?. Don't forget that you can bypass just the resistor with the second cap, parallel a resistance across the entire circuit, use different series resistors for two different cap circuits (why not three!) or any combination of the above!!! I know it sounds like crazy making, but trust me Hear me now and believe me later. The good news is that it's almost always possible to do better than you hoped once you get past the straight cap circuit. The bad news is that you'll need to reinvent the damn thing for every guitar!!! It gets even more complicated for guitars with multiple pickups. The variable and dynamic impedance soup that IS the guitar pickups, their associated circuitry and the specific acoustic resonances of the guitar itself make the best circuit for any given guitar and pickup combination WIDELY VARIABLE. If someone had ever come up with a do all circuit for this every guitar would come wired that way. Also, idealizing is such a hassle, and personal taste so variable that even manufacturers don't bother with much outside of a straight cap circuit.

[J M Fahey]

I have no problem with values. I know exactly what i want in that regard, I just want to know whether my Idea will work as I intend It to.

Just 3 parts.

I'd say trying is faster (and more accurate) than designing on a napkin ... or a simulator.

As Nike says, "just do it"

[Chuck H]

Just 3 parts.

I'd say trying is faster (and more accurate) than designing on a napkin ... or a simulator.

As Nike says, "just do it"

Like again!

[Steve A.]

Solder leads with jumper clips and you can test and test and test until the cows come home. At least if you are playing a guitar like a Gibson with back access to the controls. For a strat you can remove one of the pots and run the leads through the hole.

I have not felt the need to add anything to my volume pots since I switched over to the 50's wiring for the tone pots.* Before I switched I found that a 180pF worked fine for most pickups.

Did I already suggest hooking up the two different cap/resistor combinations to a push-pull tone pot?

I'm not looking for some magical tone when I turn down the volume control- I just don't want it to get muddy and that it will hopefully keep the same tone as long as possible when turning down the pot.

Steve Ahola

* the cap or jumper going to the tone control is connected to the wiper and not to the hot outside terminal of the volume pot. One of these days I am going to hook up a push-pull pot so that I can do a direct A/B test of 50's wiring vs modern wiring.