What does Capacitor on Volume pot do?

bubbahotep2k3

bubbahotep2k3

New member
Hi guys,

On my Ibanez Rg-570 there is a capacitor on the volume pot labeled "331". I have a few questions, and appreciate any help:

(1) What is this thing doing? I know on the tone pot capacitors affect the amount of treble loss, but what about on a volume pot? Same thing? Or is it there to simply help retain the high frequencies as you turn down the volume knob?

(2) I looked up 331 on a capacitor code chart and it said .18 µF is that correct or is it really 330 pF capacitor (= .00033 microfarad) as I have read here: http://www.jemsite.com/forums/archive/index.php/t-13637.html
Btw I found the capacitor code chart here:
http://www.renderedelement.com/documents/Capacitor Codes.pdf

(3) How would tone/sound be affected if I replaced the capacitor on the volume pot with this one:
TC203M - .02 MFD Capacitors-Monolithic
.02 Microfarad Monolithic Ceramic capacitors (typical tolerance of +/-2%)
From: http://guitarelectronics.zoovy.com/results.cgis?catalog=&keywords=capacitor&x=0&y=0

(4) Finall, how easy is it to destroy a capacitor while soldering? Are they very susceptible to heat or are they pretty resilient?

Thanks,
Bubba
 
Re: What does Capacitor on Volume pot do?

A small value capacitor across the volume pot is used as a ‘treble-bleed’, allowing some higher frequencies to pass as the volume is turned down.

Usually a .001uF cap works well.

Yes, caps can be damaged if too much heat is applied. Ceramics are more tolerant than poly / metal foil.
 
Re: What does Capacitor on Volume pot do?

so i can use a volume pot with no capacitor and assuming the volume is always on 100% max there is no disadvantage to not having the capacitor, right?
 
Re: What does Capacitor on Volume pot do?

bubbahotep2k3 said:
so i can use a volume pot with no capacitor and assuming the volume is always on 100% max there is no disadvantage to not having the capacitor, right?
Click to expand...
No prob if you don't have the cap. Some folks like having it but a lot don't.
 
Re: What does Capacitor on Volume pot do?

Well even with the pot at 100% the cap will have a slight effect on your tone. At least in my opinion (and from my own experience). It seems to add a little bit more High end. Which can be good, and can be bad. Depending on how your pickups sound to begainwith, and also depending on acoustic qualitys of your guitar.
If your guitar is very bright, and your useing fairly bright pickups, The Cap is only gonna make that brighter (or shriller depending on how ya hear it). But if the guitar seems dark to you then removeing the cap is only gonna make it darker (Which could be either good or bad).
But weather you use a cap or not, the volume control will still function normally. It will just sound slightly different depending on weather you use a cap or not (and also depends on, the value of the cap, what its made of, etc..).

I say try it both ways. See which sounds best to YOU. Also try out a few different value caps if ya feel like it. They'll make tiny difference's in tone. But caps are really cheap, so its not like you'de waste to much money trying em out.......Ed
 
Re: What does Capacitor on Volume pot do?

Thanks, I want to darken my tone a little bit so I will remove the capacitor from the volume pot...
 
Re: What does Capacitor on Volume pot do?

Just to be absolutely sure there is almost no tone difference between a volume pot at maximum volume and no capacitor and a volume pot at maximum volume and a capacitor, right? (Assume no exotic capacitors here just the average ones found on volume pots by major manufacturers, in my case ibanez...)
 
Re: What does Capacitor on Volume pot do?

bubbahotep2k3 said:
Just to be absolutely sure there is almost no tone difference between a volume pot at maximum volume and no capacitor and a volume pot at maximum volume and a capacitor, right? (Assume no exotic capacitors here just the average ones found on volume pots by major manufacturers, in my case ibanez...)
Click to expand...

There IS a tone difference....but a very tiny one. Removeing the cap should darken your tone a bit. But its not gonna muddy you up or anything, so don't worry. The general feel and balance of the pickup will stay the same. Just all shrillness will be dropped sumwhat (but not nessicarilly completely).
YOu could also try putting a larger value pot as the tone cap. Cause even when the tone is at 100% its still in the circut makeing a little bit of tonal difference.
Try changeing it to .47uf and it'll darken yer sound up a tad too. And a .47uf cap always seemed to bring out more lower mids to me. But Thats just what MY ears hear. yours will hear it differently......Ed
 
Re: What does Capacitor on Volume pot do?

Hey Low, I think I am gonna disagree here, and maybe Artie, the electronics master can give a more accurate explanation, but I don't think that the volume cap mod has any effect when the volume pot is in its full clockwise position. It would pretty much have to be an active circuit in order to "add" any treble to the signal, because at that point the resistance of the pot is so low.
I might be wrong. Artie would know for sure, I would think
 
Re: What does Capacitor on Volume pot do?

DracoAran said:
Hey Low, I think I am gonna disagree here, and maybe Artie, the electronics master can give a more accurate explanation, but I don't think that the volume cap mod has any effect when the volume pot is in its full clockwise position. It would pretty much have to be an active circuit in order to "add" any treble to the signal, because at that point the resistance of the pot is so low.
I might be wrong. Artie would know for sure, I would think
Click to expand...

Thanks for the vote of confidence, and you are exactly correct. :)

If the treble bleed mod is wired as shown in this diagram . . .

Treble bleed Mod

. . . then the cap and resistor are shorted out at "10" on the volume control. They can't have any affect. I suppose it would be possible that a faulty pot might still have some resistance when its full up, but I've never seen that happen. (At least, that I can remember.)

Also, bubba is correct that "331" on a cap should be 330pf.
 
Re: What does Capacitor on Volume pot do?

It does what chaos said in the second post. It allows some high-frequencies to bypass the volume control as you turn down the volume. A variation of the "50's mod".
 
Re: What does Capacitor on Volume pot do?

So I could do this to compensate the effect of that wiring for multiple volume pots (remember that thread?) where it's like i have a 500k Pot when at 10, and a 250k at half and stuff...
 
Re: What does Capacitor on Volume pot do?

ARtie, what is the "331" capacitor doing on the ibanez though? Its too high of a value to be a treble bleed trick, no?
 
Re: What does Capacitor on Volume pot do?

bubbahotep2k3 said:
so i can use a volume pot with no capacitor and assuming the volume is always on 100% max there is no disadvantage to not having the capacitor, right?
Click to expand...

If the pot is 0Ω between input end and wiper when at 100% rotation then the bleed capacitor is completely shorted and cannot have any effect at all.
 
Re: What does Capacitor on Volume pot do?

Zombie thread.

But I'll throw in my two cents and say that 330 pf. seems a bit high.

My PRS guitars (two CU22's and two SE Singlecuts) came with a stock 180 pf. cap across the volume pots.

That's plenty of treble bleed for me.

Works very well. Just enough to make a difference but not so much that my guitars sound too crisp or too edgey.
 
Re: What does Capacitor on Volume pot do?

PFDarkside said:
Lew, have you ever used any sort of treble bleed on a Strat?
Click to expand...

Yes. On a Strat and on a Tele too.

Couldn't get it right. Always sounded too sizzley. Especially on a Tele.

Eventually decided that Fenders didn't need it the way humbuckers sometimes do.

Some treble bleed options:

Lindy Fralin: 2200 pf cap and 220K resistor
John Suhr: 680 pf and 150K resistor
Kinman: 1.2nf and 130K resistor in series
 
Re: What does Capacitor on Volume pot do?

I use 120k resistor with 500k pots. Originally added it to smoothen the taper, but (with pickup in wiper side) it seems to work as well as cap does. It's better really, since doesn't add any highs, just reduces the loss.
 
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