Earthing

[MariaOrsic]

Hi all

Please can you advise on the best way to earth these things?

Do you recommend drilling a hole in tbe alloy case and bolting the connector in or perhaps soldering direct to the case?

Any advice gratefully received.

Thanks

[Seljer]

You're not going to solder anything to aluminum, forms an oxide layer to quickly for anything to stick.


People generally rely on the mechanical contact on the input/output jack to make sure the enclosure is earthed.

[tdkrause]

One of the things I like to do is use the grounded lug on my volume control (assuming you are building an effect that has a volume control). I solder a short wire to the crimp on the grounded lug that forms an eyelet and place the other end of the wire right next to the threads on the shaft. That way, when everything is tightened down, the wire is pinched between the pot case and the enclosure, thus grounding the enclosure. Depending on the type of circuit, it might not need to have a grounded enclosure. The circuit has a solid ground connection through the guitar cable, so the enclosure just acts as additional shielding. Some circuits are just as quiet outside the box as they are inside, but if you are building a high gain or other high sensitivity circuit, definitely ground the enclosure.

[karbomusic]

You're not going to solder anything to aluminum, forms an oxide layer to quickly for anything to stick.

A couple of years ago I purchased a 50 foot roll of copper tape with conductive adhesive to shield a guitar. It is very hard to remove once sealed and I solder to that. I don't actually need to do it that way very often since my output jack at minimum is ground to the box but when I do it works like a charm.

[R.G.]

To get a good connection to an aluminum box, use a  connection which is retained by a nut that will not be frequently removed. Put an external-tooth lock washer under the nut. The teeth have edges that bit through oxide ( and paint, and other goo) into the metal underneath. There are small points of the teeth that form what the industry calls a "gas tight high pressure" contact, the same as the theory about what happens to wire at the corners of wire wrap pins. That's why they're square with sharp corners, by the way.

These many microscopic points have sufficiently high pressure that they keep atmospheric oxygen out and stop corrosion, giving a reasonably reliable contact.

[garcho]

"Depending on the type of circuit, it might not need to have a grounded enclosure."

Name an audio circuit that's not improved by grounding the enclosure. I wouldn't bother wondering which is which; ground all enclosures. Use metal jacks and forget about it.