Grounding enclosures with isolated jacks ... there's gotta be an easier way

[midwayfair]

I've been soldering a wire to the side of the enclosure down by the switch to ground the enclosure. This has more than a few obvious problems, mostly that it (a) looks kinda dumb and (b) comes off if it's bumped at all because soldering to aluminum is stupid.

There's got to be an easier way. My initial idea was to simply run a wire from the ground lug on a jack to between the enclosure and the jack, then tighten the nut ... this probably isn't excellent contact, especially if there's paint in the way, but it should work a little.

Is there some other way to do this that would make even more sense?

[theehman]

Why not just put a small bolt (like a 4-40) through the chassis with a solder lug?

[defaced]

Some pot casings can be soldered to, others have to be sanded a little, but it can be done.  Simply run a wire from the ground on the PCB to the back of (1) pot casing.  When the pot is installed, the circuit is grounded to the enclosure. 

[garcho]

This is going to show how little I understand about electronics and electricity, but how is an enclosure earthed if it sits on rubber feet?

[Mike Burgundy]

There are also toothed washers available with a little solder tab. No idea where exactly, but I've seen them around. Just stick one over the input jack before installing it in te box (so the washer w/tab is inside the box) and solder to that.

[defaced]

This is going to show how little I understand about electronics and electricity, but how is an enclosure earthed if it sits on rubber feet?

Through the sleeves on the jacks which run to the amp, who's circuit is Earthed.  In this particular case though, "grounded" means the 0v supply rail for the pedal, not physical Earth.  A stomp box will work just as well with a battery powered amp that has no Earth connection, though that setup may be a bit more noisy.   

[davent]

There are also toothed washers available with a little solder tab. No idea where exactly, but I've seen them around. Just stick one over the input jack before installing it in te box (so the washer w/tab is inside the box) and solder to that.

Keystone solder lugs. http://www.digikey.com/catalog/en/partgroup/solder-lugs-keystone-electronics/23320

[electrosonic]

Somewhere, maybe way back in the pictures thread, I saw someone use a battery terminal to connect the pcb to inside of the enclosure. One of these...


Keystone part No. 629

mounted at the side of the board, so the spring  touches the enclosure when the pcb is secured. I am not sure if oxidation would be an issue in getting a consistent connection.

Here is the part in the mouser catalog.
http://ca.mouser.com/ProductDetail/Keystone-Electronics/629/?qs=%2fha2pyFadugnJ3LqyhihDIRKZmiZueCQsdggmYRNykg%3d

Andrew.

[garcho]

I guess I still don't understand. My dc jack, battery, and pcb are all grounded to the sleeves of both 1/4" jacks, so why would I ground the enclosure? Is it so I don't have to connect the sleeves of each jack with a wire? Thanks

[Jdansti]

I guess I still don't understand. My dc jack, battery, and pcb are all grounded to the sleeves of both 1/4" jacks, so why would I ground the enclosure? Is it so I don't have to connect the sleeves of each jack with a wire? Thanks

Sometimes paint insulates or causes high resistance keeping the jacks from having a good connection to the enclosure.  I've seen people have problems by not using a ground wire on one of their jacks thinking that the other jack which had a ground wire was provinding a ground connection through the enclosure.

[defaced]

I guess I still don't understand. My dc jack, battery, and pcb are all grounded to the sleeves of both 1/4" jacks, so why would I ground the enclosure? Is it so I don't have to connect the sleeves of each jack with a wire? Thanks

Shielding.  And as you correctly guessed, it eliminates running a ground wire to the output jack because the enclosure works as the return path for the output jack.  I'm not a fan of this method, but it's common and can work. 

[midwayfair]

Thanks for all the suggestions.

I'll look into the washers with solder lugs. Soldering to the back of the pots would be an option in larger enclosures, but I forgot to mention that this is primarily for 1590A builds with 9mm pots with plastic cases.

re: sanding, I usually scrape the side with a screwdriver to get nice deep accretion points. The solder "takes" but it comes off if it's ever nudged. I really just wanted something more durable and it sounds like the washers will be it.

[electrosonic]

Here is a relevant quote from "The Circuit Designer's Companion", by Tim Williams. (great book btw)

"The best connection (since aluminum can not be easily soldered) is a force fit or welded stud. but if this is not available then a shakeproof serrated washer should be used underneath the nut which is in contact with the aluminum"

Andrew.

[John Lyons]

I guess I still don't understand. My dc jack, battery, and pcb are all grounded to
the sleeves of both 1/4" jacks, so why would I ground the enclosure?

Isolated jacks is the concern in this topic The plastic type that aren't making
metal to metal connection to the enclosure.

[garcho]

I was curious because I use isolated jacks as well, but only because I got a great deal on a bunch of them, not because of any technical reason. I forgot about the RFI thing. I don't ground my enclosures, and I don't have any noise problems, but I will look deeper into this now, thanks dudes!

[davent]

The 'solder tabbed' toothed washers work well but are only available for small screw sizes necessitating another hole usually for that screw alone, be nice to find tabbed toothed washers that were big enough to be used on the footswitch. When using isolated jacks i'll make a solder tab that fits around the base of something that's already being mounted and ground the enclosure using that.

This one's to ground a guitar pickguard.



Bottom left corner, power jack has the tabbed hookup.




dave

[midwayfair]

^ Dave, that enclosure setup is awesome. Good call on the little loop ... that would be super easy to rig with the low profile jacks I use a lot, or I could even put it around the footswitch and solder it to the ground lugs.

[pinkjimiphoton]

i use isolated jacks on my pedals now...i just run a bit of bare wire around the plastic thread of my input jack, then connect that to the star ground. done deal.

also tried doing it around the switch, but that can give an intermittent ground if the switch moves at all.

[Processaurus]

Couple other ideas, apologies if it's been mentioned before:  You could solder a ground wire to a pot's shell, like on guitars.  Or, if the board is mounted on an aluminum standoff (one of the best ways to secure a circuit board on a box), one of those washers with the wire thingy you crimp onto your ground wire can get bolted on there with the PCB.  Or, better yet, the PCB itself has a grounded pad around the hole for the standoff.

Or like others were saying, just stick a screw through the enclosure and hold a ground wire on with a nut, and be done with it.

[Processaurus]

Weird side question, have you seen fancy new digital pedals, like boss and line 6, never connect chassis ground and circuit ground directly, but connect them in several points through small value surface mount caps?   What benefit could this have?