RE: OT question about sound cards/chip-sets and high-end musicsystems
Paul E Condon wrote:
> long adapter cable (>~100ft). The cable would be carrying analog
Unbalanced signals, such as might be found on computer sound card 1/8"
TRS jacks and audio equipment RCA jacks, are susceptible to common-mode
noise and ground loops. If your computer sound card line out jack and
your pre-amplifier/ receiver line input jacks are grounded to your
electrical power distribution system, directly or indirectly (e.g.
3-prong power cable to anything connected to either), connecting your
computer to your audio gear will create a large single-turn transformer
with your equipment and house as the core. Induced currents would
result in common-mode noise; you might hear your electrical appliances
through your audio system. (I was able to hear my refrigerator
switching on and off in one apartment; I can see my garbage disposal
operating in my current house.) Electrical system ground faults, arc
welding, etc., could damage your audio gear and/or computer.
Balanced signals are designed to reject common-mode noise. I've sent
line-level public address signals from a mixer to a series of amplified
loudspeakers using ~800 ft. of XLR cables with no perceived loss in
Isolation transformers can connect balanced and/or unbalanced systems,
and break ground loops. (Good direct boxes incorporate a transformer
and include a "ground lift" switch.)
The fast, cheap answer is to buy 100+ ft. of twisted, shielded pair
(TSP) cable, run it, make up the ends, and take a listen. Adding load
resistors at the audio end might reduce common-mode noise (observe sound
card line out load impedance specifications). If it sounds okay, tape/
staple down the cable and you're done.
Two 100+ ft. cables would give you less cross talk.
Two isolation transformers/ direct boxes and two cables would be a
reasonable best effort.
That said, I still think you'd be better off with an HTPC (with wireless