Grounding question

scotsman · June 26, 2006, 02:22:09 PM

I was just wondering - I'm working on a couple of projects where the LED is very close to the edge of the enclosure. Is there any reason why I couldn't simply ground the negative lead directly to the interior of the box?

nelson · June 26, 2006, 02:24:02 PM

Soldering to an aluminium enclosure is impossible with the soldering irons we normally use.

scotsman · June 26, 2006, 02:24:49 PM

Even if I roughed it up with my Dremel?

petemoore · June 26, 2006, 03:16:32 PM

Bolting an eyelet to the aluminum chassis is the easiest method to connect to it.
I create a circle with the end of the wire, solder that and use it as an 'eyelet', bolt it to the aluminum.
Aluminum takes a special welding technique, probably different for different types of aluminum.

scotsman · June 26, 2006, 03:55:48 PM

Quote from: petemoore on June 26, 2006, 03:16:32 PM
Bolting an eyelet to the aluminum chassis is the easiest method to connect to it.
I create a circle with the end of the wire, solder that and use it as an 'eyelet', bolt it to the aluminum.
Aluminum takes a special welding technique, probably different for different types of aluminum.

Found the easiest solution - I just ran it to the output jack sleeve. Close, easy and neat!

petemoore · June 26, 2006, 04:28:28 PM

Yupp...right there...same thing but already there !! Jacks clamp good to ground box.

grapefruit · June 26, 2006, 04:46:18 PM

If you do a search on switch pop or something similar you'll discover why it's not a good idea to connect the LED cathode to the input or output jack GND. It's best to have the LED GND to go back to the main filter cap or battery. Saying this, I use insulated jack sockets. If your sockets are connected to the case and it's a good solid GND then it may not be a problem. (ie: The battery GND connects to the case)

Stew.

scotsman · June 26, 2006, 05:36:07 PM

Quote from: grapefruit on June 26, 2006, 04:46:18 PM
If you do a search on switch pop or something similar you'll discover why it's not a good idea to connect the LED cathode to the input or output jack GND. It's best to have the LED GND to go back to the main filter cap or battery. Saying this, I use insulated jack sockets. If your sockets are connected to the case and it's a good solid GND then it may not be a problem. (ie: The battery GND connects to the case)

Stew.

The box is switchless or "always on." - So no worries about pop etc. No battery either (wouldn't fit anyway) as I'm using a Hammond 1590LB 2"x2"x1." External power only! Im also using Neutrik jacks - so they are connected to the case.

petemoore · June 26, 2006, 10:29:04 PM

Whoops thanks...
Stew may be right about that, something I hadn't considered.
I've read of LED's switched to indicate function making pop in the effect, if it's not a problem it's Not a problem...
Just thought I'd un-clarify a bit..

grapefruit · June 27, 2006, 03:36:12 AM

Cool, in this case is should be fine then. I guess it's just a power indicator LED.

While we're talking grounds, the thing about connecting the socket ground to the main filter cap (or after it) still applies if you're usind an external power supply. Hopefully you're using a regulated supply, in which case it shouldn't be a big deal - just good practice. (ie: don't go from the power connector - to the sockets - to the PCB and filter cap). With an unregulated supply you can get charging currents going down the GND wire from the sockets, causing hum.

Hope this made sense. It's been a long day!

Stew.

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Grounding question