Wiring question: balanced vs ground compensated

[Akira]

What is the rule when wiring a mixing console with ground compensated outputs to a hard disk recorder with balanced inputs?

All connections are TRS
console: Tip=hot/ Ring=ground sense/ Sleave=ground
recorder: Tip=hot/ Ring=negative/ Sleave=ground

With an unbalanced output connected to a balanced input the system is reduced to an unbalanced line. But, with a ground compensated system does this condition still apply? Is there any advantage to using isolated TRS connections throughout the chain?
What is the difference (advantage) between ground compensated and unbalanced?

Thanks

[ralphs99]

Hi Akira,

It's a good question! I've never seen this arrangement before. It appears that a ground-cancelling (compensated) output is an unbalanced output. But a very clever one.


Usually differences in Earth potentials between pieces of equipment are cancelled out by subtraction with a balanced input stage in the receiver. In the case of a ground-cancelling ouput, the same thing is achieved by addition in the output stage of the transmitting device.

In either case, if you are driving a balanced or unbalanced input, you should ideally connect R&S together at the receiver end. This is done to enable the ground cancelling scheme to operate correctly.

So yes, there is an advantage to running balanced TRS everywhere.

However is a small studio setup you could argue that the Earth potential differences are relatively small. Thus if money were an issue, you could run everything unbalanced and just connect T&S via an unbalanced 1/4" plug at the driving end.

There is more info at:
http://www.dself.dsl.pipex.com/ampins/balanced/balanced.htm
figure 5a.

Cheers, Ralph

[Akira]

This forum never ceases to amaze me.
I posted this question on gearslutz.com (gear maniacs and recording engineers) and no one new what I was talking about. And to think, some of those guys own million dollar studios, and most of them work full time in the industry.
There's an eclectic bunch here...who also are more than willing to share knowledge.
JBL...1 gearsutz...0:applaud: