Grounding to back of pot

[skern]

Hi guys. I have a question about grounding for a simple circuit I'm planning. If I want to connect all ground connections to the same spot, how do I do this? I mean, if I connect a wire to each ground connection (5 total), should I then attempt to connect the other end all the wires together into one bigger wire, and then connect this to the back of the pot (or wherever)? If that's the case, should I just twist the wires together and then tin them with solder?

Also, regarding connecting to the back of the pot, this is what I was originally planning, but I have an Alpha pot and I've read that they don't work so well with this method. What's the next easiest way? I read about drilling a hole for a bolt and using that, which seems pretty easy. I should mention that this isn't a typical guitar pedal with an in and out for the guitar signal, rather it's a pedal for creating CV/expression to connect to other pedals.

[GibsonGM]

Same with everything, really...if it's powered, take all your ground to one spot on the PCB, then that connects to battery " - " for negative ground circuits.  This can happen thru a jack used for switching the PCB on and off, as most pedals do.   I wouldn't sweat star grounding TOO much, just be aware of it and try your best.  I wouldn't use a pot for my 'main ground', in case it comes loose...using the jack switch method, that jack will connect to the enclosure and ground IT as well, shielding your circuit (as long as it's not an isolated jack).

[skern]

Same with everything, really...if it's powered, take all your ground to one spot on the PCB, then that connects to battery " - " for negative ground circuits.  This can happen thru a jack used for switching the PCB on and off, as most pedals do.   I wouldn't sweat star grounding TOO much, just be aware of it and try your best.  I wouldn't use a pot for my 'main ground', in case it comes loose...using the jack switch method, that jack will connect to the enclosure and ground IT as well, shielding your circuit (as long as it's not an isolated jack).

The thing is, I don't have a PCB, or a battery, and I'm dealing with isolated jacks...

[idy]

Your box is control voltage, no audio inside, so grounding the box and etc. is not very important. All ground wires together.

[GibsonGM]

Same with everything, really...if it's powered, take all your ground to one spot on the PCB, then that connects to battery " - " for negative ground circuits.  This can happen thru a jack used for switching the PCB on and off, as most pedals do.   I wouldn't sweat star grounding TOO much, just be aware of it and try your best.  I wouldn't use a pot for my 'main ground', in case it comes loose...using the jack switch method, that jack will connect to the enclosure and ground IT as well, shielding your circuit (as long as it's not an isolated jack).

The thing is, I don't have a PCB, or a battery, and I'm dealing with isolated jacks...

Yeah, umm, LOL.  What IDY said...not enough coffee sometimes and I skated right over your "CV" remark.  No worries at all!    What I said would hold true only for something you'll hear.

[Phend]

Don't use the back of the pot. It can be a mess. See pic of store bought effect. 4 maybe 5 connections.

[antonis]

A washer with soldered all ground wires shouldn't be convenient..??

[Steben]

Don't use the back of the pot. It can be a mess. See pic of store bought effect. 4 maybe 5 connections.

Are you laughing with vintage amp wiring??

[Phend]

Are you laughing with vintage amp wiring??

It works !! This is the receipt for the Muff Fuzz shown above.(I am not using those strings for $4.40 anymore, just replaced them)

[skern]

Your box is control voltage, no audio inside, so grounding the box and etc. is not very important. All ground wires together.

Ah, that's reassuring, thanks. Still, I guess one of the things I was wondering is what is the easiest way to join all the wires together? I've seen 2 wires twisted together, but not 5.

A washer with soldered all ground wires shouldn't be convenient..??

So, a washer attached to the inside of the pot?

[antonis]

So, a washer attached to the inside of the pot?

Yes, in case of grounded metal box..
You can use more than one washers in case you find difficult to solder 5 wires onto same washer..

[skern]

So, a washer attached to the inside of the pot?

Yes, in case of grounded metal box..
You can use more than one washers in case you find difficult to solder 5 wires onto same washer..

This is one part that still doesn't sit well with me. I don't know how to tell if the box is grounded. Does that just mean that the ground wire from the power jack is at some point connected to the box or a metal part that is in contact with the box? Sorry for the n00b question.

[davent]

One wire from the metal box to the ground trace on your pcb will ground all metal objects in contact with the box. I've used a piece of solid wire wrapped around the threads of a insulated jack then trapped between the jack and enclosure as my box ground, instead of the washer idea.
There are small toothed terminals you can bolt inside the enclosure and wire to the pcb. I've used these, available for different sized screws.

https://www.digikey.com/product-detail/en/keystone-electronics/7311/36-7311-ND/316684
dave

[antonis]

This is one part that still doesn't sit well with me. I don't know how to tell if the box is grounded. Does that just mean that the ground wire from the power jack is at some point connected to the box or a metal part that is in contact with the box? Sorry for the n00b question.

No noob questions..
(some of us didn't know the "ground" term till recently - and some still don't..)

Basic (mother) ground for a particular circuit is considered power supply negative pole (battey minus lug)
(ignore for the moment all those guys comming with bad intentions 'cause they're positive ground Ge FFs seduced..)
From there start and there end all particular ground points..
So, metal box can either be grounded directly (a wire from PS ground to boxes body utilizing any conductive connection device) or indirectly (e.g. via the already grounded sleeve of a jack)

In practice, a combination of the above is utilized to prevent "loose" nut/bolt connections and also save great wiring length..

[skern]

I've used a piece of solid wire wrapped around the threads of a insulated jack then trapped between the jack and enclosure as my box ground, instead of the washer idea.
dave

If I use this method, does that mean I don't have to separately connect the ground lug of that jack to anything? In other words, is the ground lug already connected to the threads?

[davent]

I've used a piece of solid wire wrapped around the threads of a insulated jack then trapped between the jack and enclosure as my box ground, instead of the washer idea.
dave

If I use this method, does that mean I don't have to separately connect the ground lug of that jack to anything? In other words, is the ground lug already connected to the threads?

Open frame jacks such as these, you can see the threaded bushing is the ground contact for the plug,



Metal mounting bushing, connected to ground tab.

Closed jacks, plastic bushing, no ground connection to the inserted plug or the metal box so need to wire the ground tab to the pcb or common ground point.

[idy]

SOmeties we put five or more wires together, solder, then put some heat shrink tubing over the mess. Easy. Neat.

[skern]

Open frame jacks such as these, you can see the threaded bushing is the ground contact for the plug,

Metal mounting bushing, connected to ground tab.

Closed jacks, plastic bushing, no ground connection to the inserted plug or the metal box so need to wire the ground tab to the pcb or common ground point.

I have one of these. It looks like the sleeve lug connects to the threaded portion, I think.... right?

EDIT: I guess I could confirm this with a quick continuity test?

EDIT 2: There is most definitely continuity between the ground contact and the threads.

[davent]

Open frame jacks such as these, you can see the threaded bushing is the ground contact for the plug,

Metal mounting bushing, connected to ground tab.

Closed jacks, plastic bushing, no ground connection to the inserted plug or the metal box so need to wire the ground tab to the pcb or common ground point.

I have one of these. It looks like the sleeve lug connects to the threaded portion, I think.... right?

EDIT: I guess I could confirm this with a quick continuity test?

Yes and yes, the continuity test would also reveal if things are not as they may look to be, an invisible break or other anomaly.
dave

[skern]

Yes and yes, the continuity test would also reveal if things are not as they may look to be, an invisible break or other anomaly.
dave

Ok, cool, I did the continuity test and it reveals what I expected.

One last question! So, if the sleeve contact is connected to the bushing and the bushing is connected to the box, can I just use the sleeve contact as the common ground point for the other ground connections (which, at this point, I've reduced to just 2), instead of using an additional washer or attaching more wire around the threads?