Hi, Kurt,

In the studio I built last year, I wired all with type AC (aka "BX") 
cable where the power is inside and armoured metallic sheath, so the 
power starts out well shielded. This also provides a substantial 
ground. I have the ground ringing the main operations area of the 
studio, and the power panel for the studio is in the middle rear, so 
there is little chance of any ground voltage differential between any 
two points in the studio.

Wherever possible, I use balanced interconnects.

I keep low-level, unbalanced interconnects short, away from AC power. 
My turntable preamp is right next to the turntable and connected with 
well-shielded cable. In fact, the shields are only grounded at one 
point so, while not balanced, there is no possibility of a ground 
gradient superimposed on the cable.

The unbalanced connections I have are between my jackfield and the 
unbalanced equipment. In the jackfield are 4 Aphex 124A balanced to 
unbalanced converters. The jackfields are colour coded so that I know 
what's balanced and what's unbalanced. All the unbalanced stuff goes 
into the converters.

The entire monitor chain is balanced with a Blue Sky Bass Management 
Controller and 5 Mackie HR-824 monitors. I think the connection to 
the sub may be unbalanced.

I did broadcast system design professionally from 1974-1981 for 
ABC-TV, 1981-1983 for McCurdy Radio (along with circuit and product 
design), and then from 1983-2004 with National TeleConsultants. There 
are lots of little things. We had a saying at NTC "God is in the details."

Did you put "isolated ground" power in the studio? That often causes 
more hum believe it or not.

Good luck!



At 01:56 PM 4/18/2006, Kurt Nauck wrote:
>We are doing some re-arranging of our studio here at the 
>shop.  We're encountering hum from the audio cables being in 
>proximity of power cables and possibly from florescent lighting 
>(!)   Is there some way to shield audio cables from the influence of 
>power sources?  I've read that one should always cross audio and 
>power cables rather than having them run in parallel.  Any 
>suggestions would be appreciated!

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