Archived from groups: rec.audio.pro (
More info?)
On Tue, 27 Jul 2004 20:02:19 -0400, w_tom <w_tom1@hotmail.com> wrote:
> For some reason, noise is confused with surges. Is your
>computer outputting over 330 volt spikes on the 120 volt AC
>line? Read the surge protector box. Protector remains inert
>- does nothing - ignores the noise. Why? Noise is single
>digit volts. Protector does nothing until it sees hundreds of
>volts.
No, I wasn't confusing surge supression with line conditioning. I just need
help on what equimpment and what configuration I will need to adequately
address all the important issues, protecting my equipment from surges, keeping
noise out of my mixes, and protecting my data from the consequences of
outages.
> First, take that computer to another room. Run it with an
>AM radio adjacent. Does computer interfere with AM radio
>reception? Then computer is defective by design. A problem
>most often found when power supplies are purchased only on the
>spec called dollars. Classic bean counter design. If
>computer noise is affecting your audio system, then a solution
>starts inside the computer where the solution is inexpensive,
>easy, and most effective - AND required by FCC regulations.
Well, it's a Mac G5, so I don't know if there's any easy mitigation if it's
putting out too much EMF. It would be good to know, though, so I'll try that
experiment. I do know there is noise in the speakers (mostly just in the
speakers, after the amp, much less in the mix with headphones), and I've been
assuming it's via the power connections, not RF though the air, because the
Mac is not next to the Amp.
> Are audio components subject to AC line noise problems?
>Lets find out. Power them from the UPS while that UPS is in
>battery backup mode. That UPS in battery backup mode
>typically will output much more noise and spikes than any
>computer. Note a revealing fact. Plug-in UPSes in battery
>backup mode tend to be some of the largest source of 'dirty'
>electricity because plug-in UPSes don't really condition AC
>power as so many would wish.
Good to know - thanks for the tip!
> So what does the plug-in UPS do? Typically it connects its
>output directly to AC mains when not in battery backup mode.
>Where is the line conditioning? So much about electric noise,
>filters, conditioning, surges, and spikes is too often
>promoted by myth rather than by fact. Facts. Where are the
>long list of numerical specs for that UPS and for that surge
>protector? Are numerical specs hard are to find? Making specs
>difficult to obtain helps to promote the myths.
>
> You have a first step. Test that computer with an AM
>radio. You have a second step. Power audio components from
>the dirtiest (noisiest) electrical source - a plug-in UPS in
>battery backup mode.
OK, some things for my to do list.