Chassis Question

[huskydawg9]

I'm planning on building a preamp which is designed to have the power supply and linestage in separate chassis, each with their own star ground.

I'd prefer to have one large case, to avoid the umbilical but still reap the benefits of having them isolated.

So which of these ideas is better (or if I'm out to lunch...then tell me so):

1. One large aluminum case, with the sections separated by aluminum channel. Each side would have a star ground, but the entire case is electrically connected to earth.

2. One large aluminum case, with the sections separated by some insulating material such that each side was not directly connected. Although the mains on the ps side would be earthed, and the star ground on the line stage side would be earthed to that side.

[andyjevans]

A third possibility is two aluminium cases, joined at the front (and back if you wish) with a non-conductive material. Wood would be obvious for the front, but perspex or other plastic is another idea. You could then run the interconnects in a thin plastic pipe between the two boxes. Effectively you have seperate boxes.

I've been pondering this myself.

andy

[huskydawg9]

Exactly. I want the benefit of separate cases but in one case. What about a wood case with two compartments and aluminum tops/bottoms and possibly an aluminum rear panel?

[aardvarkash10]

check out poinz's line amp at audiotropic.com... Also pictures of it in the aesthetics thread

[huskydawg9]

Thanks for the clue... actually something like this is what I was thinking...

http://www.audiotropic.net/Products/mmPortrait.jpg

[boywonder]

Originally Posted by huskydawg9

Thanks for the clue... actually something like this is what I was thinking...

http://www.audiotropic.net/Products/mmPortrait.jpg

Ardvaark's link above is Poindexter's preamp, same basic design as his power amp from your link.

It seems like your choice #1 above may be prone to ground loops if the entire chassis is earth grounded (as it should be) and you have two star grounds both in a common chassis that's conductive. If you have chassis continuity between the star ground points, that may be sub-optimal, since you may have a ground loop between them if they are at different potentials.

Choice #2 seems like the way to go IMHO.

Speaking of Poindexter, he has a fair bit of info on his site about grounding and ground loops located here:

THE MUSICAL MACHINE; IMPLEMENTATION.