Capacitor Values: What does it all mean?

big_black

Opaqueologist
I am putting new pots (500K) in my strat. The pots came with .022K caps. What does the value of the capacitor mean? What are some other values that can be used, and what is the result?
 
Re: Capacitor Values: What does it all mean?

To make an analogy, picture a water "feed" pipe, and a "return" pipe. Between them is another short pipe with an elastic membrane blocking it. A pulse of water would hit the membrane and stretch it as far as it could go before it couldn't stretch any farther. Then the pulse would continue on down the feed pipe to its destination. The larger the membrane, the slower it would react, and the more water it would "absorb" before reaching its limit.

A cap is a "membrane" stretched between the poitive and ground of an electrical circuit. The larger it is, (higher micro-farad value), the slower it moves, (lower frequencies), and the more it can hold, (greater attenuation).

Thus, the larger the number, .05 compared to .022, the lower in frequency will pass through it, (to ground), and the more of the signal will make it there.

So in a guitar circuit, low numbers mean more highs. Higher numbers means less high frequencies.

Does that make sense? :)

Edit: To add one more thing. If you accidentally used a cap that was too large, its influence would carry all the way down into the entire guitar frequency range, thus, making it a volume control, instead of a tone control. I'm not sure what value exactly where that would start to happen. Probably around 1uf or so.
 
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Re: Capacitor Values: What does it all mean?

Yeah...kind of. So the lack of highs or lows, is it comparable to adjusting the tone knob? I mean, is that the kind of cut off in highs you get? I have one JB in my strat, maple neck. I split the coils at times (see sig), and its cool, it sounds almost like a tele. Cleans on series wiring are kind of muddy. I currently have 500ks in there with .002k caps, it seems to be the standard guitar techs use. Should I go with a lower value for more clarity when in series?
 
Re: Capacitor Values: What does it all mean?

big_black said:
Yeah...kind of. So the lack of highs or lows, is it comparable to adjusting the tone knob?

Yeah . . . sorta. The value of the cap effects what frequency range you'll bleed off. The value, and setting of the tone knob effect how much of that frequency range that you actually send to ground.

Think of the tone control as a big water valve, leading to my membrane, in the above analogy. A "no-load" tone control has the ability to shut-off completely, as in the cap removed from the circuit. A "normal" tone control will always allow a certain (small) portion to bleed through. To ground, that is.

As for what actuall value you should use, that depends on a lot of factors. Experimentation is good. Or perhaps someone else will chime in on that part. ;)
 
Re: Capacitor Values: What does it all mean?

They do make variable capacitors. So you could stick one in, turn it till it sounds good to you. Then take it out and measure its capacity on a fancy multimeter, and then find yourself the according capacitor.
 
Re: Capacitor Values: What does it all mean?

proxy said:
They do make variable capacitors. So you could stick one in, turn it till it sounds good to you. Then take it out and measure its capacity on a fancy multimeter, and then find yourself the according capacitor.
They don't make them hat freakin' large bud! Trust me, I've looked, I think the largest I've seen has been like 8pf~270pF ... that's not going to do anything for a tone control. Trim caps are made for selectable LC tuning of radio frequencies and up ...audio is much to low for this.
 
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