Diy DI box and inverse, ground lift help

[diydidi]

Hi
I built a DI box (BAL to UNBAL) and its inverse (BAL to UNBAL) converter, all in one box. The unit is mains powered in an old PC power supply box.
I am killing ground loop between the steel chassis/mains earth, and the signal ground by using a 100ohm//100nF cap parallel combo.
I however I can't kill a ground loop between a signal going into say the BAL input and its UNBAL output.
Where is the best place to put a ground lift switch? On the input XLR or the output TS plug?
Inversely where to put it on the UNBAL input and BAL output converter?
My thinking says put it on the XLR sockets of both sections. Any thoughts????
I will be using a 100ohm//100nF bypassed by a switch as the ground lift circuit.

 

[JohnRoberts]

Hard to say without more information.

JR

 

[abbey road d enfer]

Hi
I built a DI box (BAL to UNBAL) and its inverse (BAL to UNBAL) converter, all in one box. The unit is mains powered in an old PC power supply box.
I am killing ground loop between the steel chassis/mains earth, and the signal ground by using a 100ohm//100nF cap parallel combo.
I however I can't kill a ground loop between a signal going into say the BAL input and its UNBAL output.
Where is the best place to put a ground lift switch? On the input XLR or the output TS plug?
Inversely where to put it on the UNBAL input and BAL output converter?
My thinking says put it on the XLR sockets of both sections. Any thoughts????
I will be using a 100ohm//100nF bypassed by a switch as the ground lift circuit.

What loop are you trying to break? It depends on what you connect to your system. Probably the most likely loop is between the guitar amp and the recording set-up.
Anyway a loop is a loop; if it must be broken it probably doesn't matter WHERE you break it.
In both cases, you must break the connection between the XLR's pin 1 and the TS jack's sleeve, so you should connect the switch between these two points.