Tone Control Capacitors

[wafer-custom-guitars]

We all like to work on ways to improve what we have, get more from it, and our guitars are no exception. We look for more ways to get more sounds and more tones. There are lots of ways, and they don’t all cost a fortune. Lets look at the fitted tone control and understand what it does and how it could be changed.
The tone capacitors job is to progressively block sound frequencies generated by the guitar strings in the Pick-Ups, starting from the highest frequencies and working down into the mid-range. The tone potentiometer itself puts resistance against the generated signal, such that with the Tone Control at zero there is no resistance and all the signal goes to the capacitor, allowing the capacitor to remove the higher and middle frequencies output. At ten on the Tone Control the resistance is so high as to prevent the signal reaching the capacitor and your guitar note is pure as if there were no tone control fitted. (In truth the very highest frequencies still leak to ground). Your sound becomes progressively brighter. Turn the tone control towards zero and the frequencies are rolled back. You gradually begin to send signal through the capacitor to ground.
So, what controls how far the high and mid-range frequencies are rolled back, how far do we go? On a guitar, the capacitor works in a passive mode, allowing high frequency signals to pass through, grounding them out. The frequency cut off point is determined by the size of the capacitor. Single coils like Fenders normally use the .022 microfarad capacitor. If you increase the size of the capacitor, you effectively lower the frequency cut off point. As the tone cut off is lowered the tone becomes deeper or bass. Fender guitars in the early days, which are generally thought to be among the best-sounding guitars ever made, had the tone capacitor value of .1 microfarad or .05 microfarad. The larger value capacitor results in a darker warmer tone, which may suit jazz players, whereas the .022 microfarad capacitor is sharper and brighter, great for rock pop and blues styles. You might think that fitting a .05 microfarad capacitor, and turning the tone control half way would give the same frequency cut off as a .022 microfarad capacitor, but it doesn’t really, as the capacitance doesn’t vary, and different value capacitors will produce different tones, which is why experimenting is encouraged.

[Elias Graves]

I thought Fenders generally use an .047 nowdays?
Regardless, I've started using .015 on my humbucker guitars. It'll still get plenty dark, but not til you hit 2-3 on the control. I don't have to be quite so precise while fiddling during playing.

Have also experimented with a lot of different ypes and materials, including the mystical paper in oil caps. To my ears, the value, not the material, is the key.

The value of the pot itself will factor in as well and not all 500k pots are created equal. I've found them ranging from 420 to 570. High tolerance CTS pots and Gibson pots generally come in pretty close to spot on. Standard CTS and Alphas are all over the place.

EG

[spiral]

UG Community @ Ultimate-Guitar.Com - Tone Control Capacitors

[bananafist]

Had the opportunity to play a couple of 1956 gretsch Streamliners back to back yesterday, and very noticeable about one of them was the effect of the tone pot as rotated. It seemed to increase the bass end, and reduce the mids some, whilst still retaining some sparkle at the top end right upto the last quarter turn. Looking through the f hole the (original) pot and wiring seemed to have two caps connected. I wasn't able to dissassemble it to check it out (not my guitar) but if anyone has a schematic with values for the streamliner one pickup tone/vol circuit I'd be v. interested to see one.
Both guitars played well, and looked v. cool, by the way.

[billkath]

Probably a treble bleed ciruit--

Project Guitar :: Tweeking pot's and 3 very common treble bleed modifications

[bananafist]

billkath - no, I don't think so, or at least not one I've come across, it was far more subtle and effective than that. I've fitted a couple of these to guitars I have, and this worked much better.

[gcb]

Fully agree wtih Wafer Custom guitars. In my L5 Studio I have .05 mf polyprophilene RS Guitarworks caps and CTS pots.