Shielded cable for input signal

[falcott]

For my GC amp I intend to use shielded cable for input from RCA sockets to pot to amp input. I considered using mic cable, but I have available some lighter guage single core shielded cable (used for GPS antennas). I am seriously thinking of using this, with the shielding used as the signal earth wire.

Question: Would this work as intended (i.e. protecting the signal), or is it better if both signal and earth wires are encased in the shielding? And if so, should the shielding be left "floating" or should it be earthed to the chassis?

Thanks!

[sek]

Hi,

Would this work as intended (i.e. protecting the signal), or is it better if both signal and earth wires are encased in the shielding?

This should work well. Actually, this is how every asymmetrical signal cable connection (e.g. Cinch/RCA) is done.

Keeping "hot" signal and it's counterpart inside the shield would require a third connection for the shield, as otherwise having an earth wire parallel to the shield would have no effect on shielding the earth. Done correctly with three wires, it would require a symmetrical connection, which the usual GC doesn't feature.

And if so, should the shielding be left "floating" or should it be earthed to the chassis?

Well, despite that the answer is "not so" , wouldn't that mean that the signal return would be floating and thus only one wire connected to the GC? This would keep the circuit open and no input signal fed into the GC, if I understand the question correctly.

Hope this helps.

Sebastian.

PS: Microphones are connected symmetrically ('+', '-', 'shield'), that's why your microphone cable encloses two wires inside the shield.

[falcott]

Thanks Sebastian!
And so to work !