I have never had a problem with this. In fact, I make it a point to keep everything in the studio on 
a single 20-amp circuit. It eliminates any ground-loop problems and results in dead silence. I have 
analized the noise floor of my analog gear, including turning off all the desktop computers in the 
circuit and doing all the recording tests with a battery-operated device (Zoom 4n). There is no 
difference in the noise levels or spectrums when the computers are running. Also, no difference in 
the noise level or spectrum when recorded by battery operated device or with the PCI buss CardDeluxe 
in the PC's, or with the external Lynx HiLo.

If PCs are causing noise on the line with professional audio equipment, there is a design flaw in 
the equipment or a wiring flaw in the power circuit. With audiophillic equipment, who knows. You'd 
think at those prices, they'd build in competent shielding and grounding! There's tons of 
information about proper shielding and grounding. Anyone who has any contact with the AES has access 
to much knowledge on this. There's no excuse for building noisy equipment today.

All of that said, I have found that the old BSR home-control system and also any sort of interwebs 
on power lines usually will cause noise, particularly in high-sensitivty stuff like phono preamps. I 
make it a point to have no data or signals over 60hz riding on my inside power lines. Also, modern 
shielding and grounding was not as necessary in previous times, so some vintage equipment is very 
noisy in a modern home. Sometimes, making sure all the tubes are shielded and the shields are wired 
to a star-grounding system on the chasis can mitigate the noise. Lousy designs were always hidden RF 
receivers, and now there's more RF on more frequencies for them to pick up.

-- Tom Fine

----- Original Message ----- 
From: "Carl Pultz" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, June 18, 2014 6:37 AM
Subject: Re: [ARSCLIST] Upgrading Audio Systems

> Yeah, like having a desktop computer system plugged into the same AC as your hifi. Move it to 
> another circuit. Providing the sound system with it's own AC line (or two) straight from the panel 
> can bring hidden vitality to even a modest hifi. Power matters.
>> I suspect that, a lot of the time, mysterious differences in how something sounds turn out to be 
>> the result of out-of-band garbage making its way into the system, either via the signal cables or 
>> the wall. We live in an RFI jungle nowadays.
>> One of the biggest improvements Greg Mackie ever made to the mic preamps in his mixers was a 
>> simple upgrade in their RF-proofing.
>> Peace,
>> Paul