snake cable - drain wire connects to..??

[redrabbit]

I just soldered up a 12 channel snake cable w/ balanced 1/4" phono connectors. (that was fun ).
Canare l-4e3-p Series.

What do I do with the bare copper drain wire ?

The snake cable is being used for balanced audio IN/OUT between my computer's soundcard (RME) and an effects/synth 19" rack.

(I am not utilizing a "bus ground" in the rack. I have no hum problems thnk gd.)

=RR=

[infinia]

Hi
Mostly one connects drain/shield to source chassis (rack) gnd. Check noise floor with Soundforge software for best results. Not a problem to float it then. ADC best done at rack me thinks.

[redrabbit]

Thanks.
I have no dedicated "chassis (rack) gnd ." but will try the rack frame.....and leave the other end floating.

I guess I could try grounding it at different points, and see which gives me the lowest noisefloor.????

=RR=

[infinia]

Originally posted by infinia

Mostly one connects drain/shield to source chassis

No... do not connect it to a floating rack.
I assume this is the source and yes other end floats.

Originally posted by redrabbit
ICanare l-4e3-p Series.

Most pro racks run a bare piece of bus wire 12AWG or braid to each and every chassis in the rack.

[redrabbit]

Originally posted by infinia

No... do not connect it to a floating rack.
I assume this is the source and yes other end floats.





Most pro racks run a bare piece of bus wire 12AWG or braid to each and every chassis in the rack.

Yes, I was wrong in believing the rack would serve as a bussed ground. (I have not filed down the backs of my gear's faceplates, nor do I want to...).

But I am wondering ...if I ever decide to add a star ground (copper buss) in my rack, does that mean that I will have to lift the sheild(ground) in most of my interconnects, to eliminate ground loops?
Right now, all my cables' sheild is serving as ground, and is connected at both ends. (balanced and unbalanced connections)......maybe I'm lucky, as right now, there is no hum.

There is a good (old) thread at Recording.org, but it's lengthy, so I copied it to a file, which I'll read tomorrow:
http://www.recording.org/ftopict-6000-drain.html

=RR=

[infinia]

I understood from your first post that you are running strictly balanced. This is of course is the abs. best for ground loops and S/N perspective. To minimize the possibility of ground loops all shields are connected at one end only. The signal is not referenced to ground as it's differential, gaining about 6 dB in S/N and more not being subject to noise flowing through the shield connection.
Now if you mix a single ended conn, into the equation, then all above is lost. Then we must conn. all shields to both ends, basically ground the sh** out of everything.
Now common mode noise is a problem and could be summed at an input.