[FraGGleR]

I am going to build a simple splitter/switchbox with an input from a DAC and an analog in being split between an output to my headphone amp and to my speaker amp.  I did this before in a plastic box and had to wire grounds for all my RCA inputs and outputs.
 
This time around I am using a metal case and wanted to verify that I didn't have to use the ground wires since the chassis will act like the ground this time around.  Does this sound correct?
 
 

And in theory, I need a 2 pole 2 position switch, but for this design so I need a make before break, or a break before make if using a rotary?  Thanks!

 

[samsquanch]

Personally, I isolate my jacks from the case and do a star ground topology.  You can try using the case as a common ground, worst thing that happens is it sounds bad and you have to isolate the jacks and wire up the grounds.  You're more than likely ok using the case, I'd meter the grounds of the outer two jacks (furthest two apart) and make sure the resistance is 0, if not, like 10 ohms or higher, I'd wire up the grounds.
 
The make/break order doesn't really matter, though you should really never have two outputs feeding one output, so I'd go with a break then make.  Also, why not just use toggles?  They're cheaper than rotaries and work just fine. 

 

[FraGGleR]

Quote:

Personally, I isolate my jacks from the case and do a star ground topology.  You can try using the case as a common ground, worst thing that happens is it sounds bad and you have to isolate the jacks and wire up the grounds.  You're more than likely ok using the case, I'd meter the grounds of the outer two jacks (furthest two apart) and make sure the resistance is 0, if not, like 10 ohms or higher, I'd wire up the grounds.
 
The make/break order doesn't really matter, though you should really never have two outputs feeding one output, so I'd go with a break then make.  Also, why not just use toggles?  They're cheaper than rotaries and work just fine. 

 
Thanks samsquanch.  For something like a passive box that doesn't have a power ground, how would the star ground topology work?  All grounds going to single point (with the jacks isolated), then to what?  I haven't used a star ground for anything before.  Still a DIY beginner.
 
And as far as rotary vs toggle, I might add another input in the box, but really, I like knobs.  I am really big into the aesthetics of devices in addition to their functionality.  My plastic box switch works perfectly well, but I want to use a nicer metal case with pretty knobs.  I need new switches and jacks because I used a crapload of glue to secure the jacks and switches to box and it would be worth $15 to not have to harvest them.

 

[samsquanch]

I typically default to star ground for my projects, but honestly, just busing the grounds will probably be just fine.  Star ground would simply mean bringing all the grounds back to a single point.
 
If you're going to expand your ins/outs then yeah I'd go with rotary and get one that allows for more connections than you plan for, future expansion is a good thing.