Capacitor Wiring & Buzz

jaymenon

In an unscreened guitar, is a capacitor wired between volume and tone pot

https://i.imgur.com/43H6IPI.jpg

more likely to pick up noise / buzz compared to a cap wired between the earth terminal and casing of the tone pot?

https://i.imgur.com/avN0oSm.jpg

SteveRobinson

As I understand it, all the current that passes through the capacitor and its connecting wires goes to earth so shouldn't affect the signal.

jaymenon

Not the signal Steve, but the sort of buzz that good screening neutralises. 

I would expect intuitively that long lengths of wiring for the capacitors (as in the top photograph) would be more likely to pick up noise...

so on something like a 335, I wondered if keeping the entire capacitor, wires and all,  close to the tone pot would be advantageous...?

Funkfingers

On a 335, connecting both ends of the capacitor to the tone pot has the advantage of being easier to fit and/or remove. The runs between pots can be made with plastic-insulated single-con + shield cable, thereby minimising hum and RF interference.

jaymenon

That's useful to know, thank you both...!

CasperCaster

The first diagram may be slightly less prone to buzz. The unused terminal of the pot is the only place where noise could be picked up, and as the wiper is connected to earth that noise would be directed directly to earth.

In the second diagram the paralleled signal feeds the wiper, so any noise picked up by the unused terminal could theoretically end up imposed on the signal. 

You could always modify the second diagram. Wire the cap between the wiper lug and the back of the pot (earth) and feed the pot from the lower terminal where the cap is currently connected i.e. transpose the connections. The unused terminal will be closest to earth (similar to the first diagram) , albeit via the cap.

EDIT: Just read Funkfingers comments. My comments assumed use of regular unshielded cable. Best outcome would be combine my proposed wiring of tone control with shielded cable as already suggested. 

ICBM

Yes, that’s exactly right - having the cap between the controls is noisier than having it connected to ground, and if you have the cap at the ground end you can also shield the connection between the pots. If the cap has an outer foil marking - usually a line at one end - connect that lead to ground.