[LAU] Noise update, still the case with the other interface

Arnold Krille arnold at arnoldarts.de
Sat May 26 14:35:01 EDT 2007


Am Freitag, 25. Mai 2007 schrieb Malte Steiner:
> Arnold Krille wrote:
> > Am Dienstag, 22. Mai 2007 schrieb Malte Steiner:
> >> I got some success with balanced cables (and balanced equipment of
> >> course) but I know at least one studio which is resistant even for that
> >> but maybe they got bad electricity anyway.
> > A studio not using balanced cables and with bad power? Don't go there...
> No, I didnt express myself very clear :) , of course they use and love
> balanced cables. But it didnt helped anyway, the laptop introduces hum
> there even with balanced cables and DI boxes etc...

Okay, your laptop introduces a hum and you are using balanced cables?

The shielding around the balanced cable is there to (further) suppress noise 
coming in. It has to be connected to earth somewhere and it is totally fine 
if it is connected to earth only on one side of the cable. So you could 
create a special (pair of) cable where the shielding is connected only on one 
side. This is no security risk in any way! Its just one of the benefits of 
balanced connections and similar to lifting ground in DI-boxes.

BTW: This doesn't work if the connected equipment is powered by phantom-power 
over that cable because phantom-power is providing the voltage between the 
signal-lines and the shielding. Disconnecting the shielding somewhere makes 
phantom-power stop / get bad. So mark the "lifted" cable to not use it with 
microphones. :-)

Or create only some small adaptors that lift ground on connections...

Arnold
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visit http://www.arnoldarts.de/
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