Tone Pot Wiring Confusion

[Ethdawg]

Hello SD Community,

I have a question regarding the wiring of a Tone pot. I ran across a site recently which detailed the wiring as indicating the capacitor tapped onto the hot line BEFORE the pot, and then using the pot as a variable resistor. This all made sense to me except for the part where the 2nd prong was also grounded. The website indicated that leaving anything ungrounded had the potential for noise as being an explanation for doing this.

The image attached refers to the issue I'm dealing with.

My question regarding this setup is - how would it be possible for this to work? As far as I understand it, with the tone pot bypassing the resistance to ground, wouldn't the signal pass through the cap (the highs) and then when faced with the full resistance of the cap, go straight to the pot's output, which is also connected to ground? This would seem to completely negate using a tone pot in the first place, since at position 0 and position 10 the signal is going to ground either way!

Any clarification would be greatly appreciated.

 

[LJ King]

Re: Tone Pot Wiring Confusion

Hello SD Community,

I have a question regarding the wiring of a Tone pot. I ran across a site recently which detailed the wiring as indicating the capacitor tapped onto the hot line BEFORE the pot, and then using the pot as a variable resistor. This all made sense to me except for the part where the 2nd prong was also grounded. The website indicated that leaving anything ungrounded had the potential for noise as being an explanation for doing this.

The image attached refers to the issue I'm dealing with.

My question regarding this setup is - how would it be possible for this to work? As far as I understand it, with the tone pot bypassing the resistance to ground, wouldn't the signal pass through the cap (the highs) and then when faced with the full resistance of the cap, go straight to the pot's output, which is also connected to ground? This would seem to completely negate using a tone pot in the first place, since at position 0 and position 10 the signal is going to ground either way!

Any clarification would be greatly appreciated.

First highlight. Some people believe this, but I've never had it happen in practice.

I've wired up many Tele's with 4-way wiring - the stock way that leaves the neck coil disconnected on one end in certain positions - and haven't had any problems with noise. There is also a modified wiring that shorts that loose end of the coil with itself - to reduce the noise potential - and there hasn't been any reduction of noise.

Plus, electricity needs a complete path. Any noise induced in the coil would have a hard time flowing with one lead disconnected.

Second highlight. This isn't going to cause any harm.

If you look at the diagram, the wiper of the pot is always grounded before the "other end" ground. Therefore, the gounding of the other end isn't going to have any effect of the amount of resistance between the cap and ground because that will always be determined by the wiper of the pot.

In other words, no difference in the resistance range of the pot regardless if the other end is grounded or not.

 

[Ethdawg]

Re: Tone Pot Wiring Confusion

...

In other words, no difference in the resistance range of the pot regardless if the other end is grounded or not.

So am I correct in assuming that wiring a tone pot this way would basically guarantee I lose all my highs no matter what? This is what confuses me, based on the diagram I assume that the highs in the signal will hit the cap, pass through it to the pot, and go straight to ground regardless of the position of the pot.

I pulled that diagram from this site if that helps any.

 

[Artie]

Re: Tone Pot Wiring Confusion

Thats the way I wire all my tone controls, but it has nothing to do with noise reduction. Electrically, its identical either way. Look at this diagram:

With the tone pot on "10", you've shorted past a short piece of wire, which affects nothing. (The full resistor is between the cap and ground.) With the tone pot on zero, you've shorted past the pot resistance. Same thing either way.

 

[Ethdawg]

Re: Tone Pot Wiring Confusion

Thanks Artie! I think it finally makes sense now.