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SSE Ground/earth question.

mudchute

Member
2012-01-29 12:23 pm
Hi all, I'm getting very close to wiring my sse up and I'd like to check with you the best ground option considering my build.

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Here's my layout, is it worth building another partition to the right of the iec plug at the bottom? The power transformer us directly above it.

And, I've read many different ideas about grounding. What's best considering my setup? I'm an electrical noob so layman's terms would be appreciated.

Thankyou all.

Gavin
 
I would start by using one of your transformer or choke mounting screws as your chassis safety ground (green wire from IEC power entry module), and bringing any other grounds over to that screw (star ground).

For electrical safety, use ring lugs for your grounds (not spades) and put internal or external star lock washers between the ring lug and the chassis deck and between each ring lug and finally between the last ring lug and the nut. If you have 3 or 4 grounds to tie to the screw you can always use a longer screw if need be. So if you have two grounds it would be lock washer-ring lug-lock washer-ring lug-lock washer-nut and so on.

When designing commercial products, the safety agencies like to see a #10 stud or larger screw, lockwashers on both sides of all ring lugs and each ring lug nutted down separately. So in this case it's lock washer-ring lug-lock washer-nut-lock washer-ring lug-lock washer-nut. Since you are homebrew, you don't need to go that far, although it doesn't hurt.

Star lock washers bite into the mating surfaces better than split locks. Ring lugs are used in case something loosens up the ground connection cannot fall off. Make sure that you don't have any surface coatings like paint or anodizing around the screw/stud.
 
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Hi all, I'm getting very close to wiring my sse up and I'd like to check with you the best ground option considering my build.
Here's my layout, is it worth building another partition to the right of the iec plug at the bottom? The power transformer us directly above it.

And, I've read many different ideas about grounding. What's best considering my setup? I'm an electrical noob so layman's terms would be appreciated.

Thankyou all.

Gavin


Looks like you're using a thick metal sheet for your chassis top plate as
well as the supports at the bottom, I doubt there would be any danger
of a sagging top plate therefore no need for further support.
 

mudchute

Member
2012-01-29 12:23 pm
Thanks guys, thats what I did for my breadboard build, I didn't realise it was an acutal technique! cool beans :)

Re the partition, the extra one wouldn't be for strength but in order to complete section off the power supply, is it worth it? I'm going to be putting the speaker terminals to the right of the IEC socket (shortest wiring path from the pcb that way) and I was concerned there might be some interference. I'm going to shield nearly everything just in case. Overkill maybe but it won't do any harm.
 
One last question, re the inrush thermistors, do they actually mount in line with the power supply wiring? So I could theoretically chop a wire and reconnect the wires with the capacitor?


Yes, and they are not caps, they just look kind of like caps. They are variable resistors. Their resistance gets lower as they heat up.

As far as your input jacks and speaker jacks go, I try to put the input jacks as far away from any AC as possible. The speaker wiring is less sensitive to AC as the signal level is higher. I also use shielded wire for the RCA jacks, although unshielded twisted pairs also can work well.
 
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