Tone pot as grounding hub question

[Inflames626]

Hi everyone,
So I have some questions that I think are pretty basic and foolish here but I want to make sure I'm clear on this.

I'm not yet at the point where I can look at a wiring diagram and think of 2-3 different wiring layouts to accomplish the same thing, but you all are helping me get there via your helpful comments on the forums. Thank you.

Until I'm better at things, I tend to look at wiring diagrams very literally because I don't understand how I can deviate from them and still be successful.

With that in mind, I see on a lot of diagrams that the tone pot is not grounded to itself. One lug is usually left alone, while there's great variability regarding cap placement.

1) If a tone pot is used as the main ground hub instead of a volume pot (because on many guitars the tone pot is closest to the output jack), ***does the tone pot need to be grounded to itself for the guitar to work?***

I've been trying to wire up a guitar with the tone pot used as the main grounding point and I can't get it to work. No output at all. I thought perhaps the pot not being grounded to itself might be the cause. However, the cap also being in the equation made me think this might be different than using a volume pot as a grounding point.

A secondary question that I don't think deserves its own thread:

2) If a tab breaks off of a pot (say from twisting and moving with pliers to better accommodate connections), is the pot still usable if the wire is soldered to what remains of the terminal?

It's my understanding that the circular holes behind the pot tabs are heat sinks. However, I thought if a wire were soldered further behind this, the pot might be usable.

I think it would be more trouble than it's worth because solder could get into the pot and onto the wiper if a wire is soldered very close to the pot body, but I only have a few linear pots.

I can always order more but if the one with the broken tab can be salvaged I'd still use it.

 

[Inflames626]

Also to clarify I ground the tone pot to the other volume pots even though this is not shown in SD diagrams.

 

[Inflames626]

Also I have the cap going from the middle lug to the pot casing per the SD diagrams.

 

[beaubrummels]

1) If a tone pot is used as the main ground hub instead of a volume pot (because on many guitars the tone pot is closest to the output jack), ***does the tone pot need to be grounded to itself for the guitar to work?***

Yes, but it doesn't have to go directly to the jack (though it would make better sense if the tone is closest to the jack). As long as there is some connection to the jack ground eventually, it will work. So for example, you could use the back of the tone pot as a central location to ground a number of wires, and you could from there ground the tone pot to the back of a volume pot and then ground that volume pot to the jack ground, which would establish a path to ground for everything else. As long as everything that needs to be grounded has a path that eventually reaches the jack ground, it will work.

But of course, the shortest path absolutely necessary would be a more advisable way to wire both hot and ground.

Also, for a tone control, the cap can be before the pot or after, because whether you have cap > resistor or resistor > cap, electronically they will perform the same way. So sometimes you will see the cap linking the volume to the tone, and other times you might see the cap just going between a tone lug and the back of the tone (grounded). Electrically they function the same in terms of their affect on the audio signal.

2) If a tab breaks off of a pot (say from twisting and moving with pliers to better accommodate connections), is the pot still usable if the wire is soldered to what remains of the terminal?

Yes. If you have metal touching metal, with the solder holding that connection together, you have a connection that can conduct electricity and will work.

 

[Inflames626]

Thanks yet again beaubrummels . Any idea why the SD diagrams don't show the tone pot grounded to the other pots?

This thing is really stumping me so I thought maybe the tone pot ground lug not being soldered to the tone pot might be what's causing the problem. I'm getting continuity between everything but still no signal.

I may go back and redo the whole thing with unshielded wire. The jack to controls run is really short and while the toggle switch is a long way away because it's an LP copy I don't think there will be enough noise to make a difference in my situation. Maybe under stage lights and such, but I'm just recording.

 

[Mincer]

I will say that some SD diagrams don't show grounds at all. We have a whole thread about diagrams that have errors or errors by omission.

 

[eclecticsynergy]

All the grounds on a guitar make up one big connection. They all connect together, and to the ground lug of the output jack.
Without that connection you won't get anything out of the guitar.

Tone pots work by diverting part of the signal to ground through a cap.
As mentioned above, it doesn't matter if the cap is before or after the pot.

If the cap is in between the volume pot and the tone pot, then one lug of the tone pot gets grounded to its casing.
If it's a plain wire from the volume pot to the tone pot, then the cap connects from one lug of the pot to its casing.
In both instances the casing of the pot needs to be connected to the output jack's ground

Attaching a wire to a broken pot lug could work if you're careful and the lug is still long enough to clip on a heat sink.
But pots are fairly easy to fry. I'd probably recommend just replacing it, especially for a relative beginner.

 

[Artie]

Maybe this is a good place to post this diagram again. Eight different ways to wire a tone pot that are all electrically and sonically identical. It helps to illustrate the versatility of tone pot wiring.

 

[Mincer]

Maybe this is a good place to post this diagram again. Eight different ways to wire a tone pot that are all electrically and sonically identical. It helps to illustrate the versatility of tone pot wiring.

Thanks for the diagram. I forget that there are so many ways to do this.

 

[GuitarDoc]

Thanks Artie. I think sometimes we overthink this idea of connecting the tone pot and we miss that there are several ways to do it and they are all the same. (Of course there are wrong ways to do it as well, but it is good to know that all of these that you have included in that diagram work perfectly).

 

[Artie]

I almost always use the lower-left version. It allows me to ground the same lug as a volume pot, and then use the cap itself as my interconnect. Works good, lasts a long time.

 

[GuitarDoc]

I almost always use the lower-left version. It allows me to ground the same lug as a volume pot, and then use the cap itself as my interconnect. Works good, lasts a long time.

Interesting. I always use the second one on the top row without any problems. But, like you said (and I totally agree) there is no difference.
Again I have to say, thanks for all of your wise contributions.

 

[Artie]

Interesting. I always use the second one on the top row without any problems.

Thanks Doc. The 2nd and 3rd one are how I see most guitars wired. If I'm doing a customers guitar, and it's NOT a total rewire, I always leave it as it is.

The reason for the bottom four, is just something that I'm probably too anal about. It's simply offers a slightly better "fault" mode. In other words, if you get a dirty pot, and if the wiper lifts for a moment, you get the tone on "10" rather than no-tone altogether. Also, I can prewire the tone pot out of the guitar, and then I only have two terminals to think about when I insert it into the cavity.

Not a big deal either way. Just an old habit.