To ground or not to ground (the enclosure)?

[joby]

So after quite a few builds, the subject of grounding the enclosure to the circuit's ground came to me. I don't see it discussed often at all. I see it in a lot of electronics, especially guitars (you know, the ground wire soldered to the trem claw on strats, and even a grounding connection to copper shielding in the electronics cavity). It essentially helps with noise, as far as I know. Is that necessary for pedals? At that point would a hand touching the enclosure effect it (negatively, pun intended) in any way?

I imagine it can be done naturally with non insulated jacks (I use insulated, so I don't like that). I've seen it done by soldering a jumper to the locking washer for the footswitch on the inside. I imagine, just like guitar, you can solder a jumper just to anywhere on the inside. Even having a hole on a PCB connected to ground for a little jumper.

So, is it really necessary? If so, what would be the best way to do it?

[merlinb]

So, is it really necessary?

Yes unless you enjoy hum and interference.

If so, what would be the best way to do it?

Any way you like. I solder a wire from circuit ground to the back of one of the pots (which is bolted to the enclosure, of course).

[PRR]

> especially guitars ...copper shielding in the electronics cavity.... Is that necessary for pedals?

The guitar signal and the pedal signal are the SAME thing.

Except the pedal may be even closer to power cords.

I can't think of any reason to not bond case to circuit common.  What ever way is easiest. Pedals are not large enough in size or current that we need any fancy grounding.

(Stay small. I'm grounding a house with 100A power in one side and telephone in the other side. I've verified the HIGH-current power ground bonds. Now I am pondering the telephone grounding. Altho wire-phones are going out of style, an overhead phone line is still a grounding/safety issue.)

[joby]

das right. i figure it wouldnt hurt at all.

[Laguna]

I may be doing this terribly wrong but:

I connect the ground on the circuit to the negative terminal of my battery.
I connect the ground on the signal (both input and output) to the same ground (- of my battery).

Is this wrong? that's what I saw in a video and that's what i do :S

[EBK]

I may be doing this terribly wrong but:

I connect the ground on the circuit to the negative terminal of my battery.
I connect the ground on the signal (both input and output) to the same ground (- of my battery).

Is this wrong? that's what I saw in a video and that's what i do :S

That's pretty close to what I do.  It's one of several equally correct ways.

[GibsonGM]

Mine are board gnd to shield of stereo input jack, ring to battery " - ", the usual way so a plug in the input jack switches effect on.   There is no 'terribly wrong' - they're all connected to battery minus! 

Of course, we're talking negative ground here   

[samhay]

I use isolated jacks and metal standoffs between board and enclosure. One of the standoffs is in contact with board ground (and the rest are isolated from the circuit).

[joby]

Ok, so I dont think you folks (GibsonGM, EBK, Laguna) understood completely what I meant. Your grounding is fine. I'm talking about also connecting the aluminum metal enclosure to ground, in addition to the jacks, board, etc.

I use isolated jacks and metal standoffs between board and enclosure. One of the standoffs is in contact with board ground (and the rest are isolated from the circuit).

Yea, that seems like another viable option. Depending on how the standoffs are fixed to the enclosure. How do you do it? Epoxy, or some conductive glue of sorts.

Thanks again, all.

[Marcos - Munky]

Ok, so I dont think you folks (GibsonGM, EBK, Laguna) understood completely what I meant. Your grounding is fine. I'm talking about also connecting the aluminum metal enclosure to ground, in addition to the jacks, board, etc.

Yeah, you surely have to connect the enclosure to ground, in any way you prefer to do it. Quoting Merlin,

Yes unless you enjoy hum and interference.

When you ground the enclosure, you're doing a Faraday's cage, which isolates everything inside of it from external interferences. If you test your circuits outside of a enclosure like I do, you may have noticed any circuit that adds gain to the signal are noisy. When they're inside the cage, most of the noise is gone. And in high gain circuits, the cage is a must. Even with a grounded enclosure in a high gain circuit, if you open the lid you'll get noises in the signal.

[PRR]

> I'm talking about also connecting the aluminum metal enclosure to ground

me> I can't think of any reason to not bond case to circuit common.

[samhay]

I use isolated jacks and metal standoffs between board and enclosure. One of the standoffs is in contact with board ground (and the rest are isolated from the circuit).

Yea, that seems like another viable option. Depending on how the standoffs are fixed to the enclosure. How do you do it? Epoxy, or some conductive glue of sorts.

The standoffs are threaded and bolted to the enclosure. I appreciate this aesthetic may not appeal to all.
You may struggle to find electrically conductive metal adhesives though.

Merlin's approach is a good one too. While I'm not a fan of soldering to the back of a pot, this is how almost every electric guitar is built, so is certainly viable. 

[Phoenix]

Many PCB mount pots, specifically those types which have mechanical solder terminals as well as the electrical ones, have those mechanical terminals terminated to the bushing of the pot (if it is a metal bushing), so that will make electrical contact with the enclosure.
This is my preferred construction method, and offers multiple redundancy if there are multiple controls on the effect. There is no issue with ground loops with multiple terminations either, so long as isolated jacks are used, as the chassis/enclosure will then not be carrying any current.