----- Original Message -----
From: "Mike Richter" <[log in to unmask]>
> D Basson wrote:
> > Dear Rod, Mike, Lou, Richard, Joe, etc.
> > Thank you very much for your advice!
> > I've disconnected the monitor and recorded "silence", but the buzz (like
> > a shaver) was still present. I've removed the I/O box from the PC case
> > and everything sounded much better. One thinks of upgrading one's
> > system (in need of speed) just to encounter new problems slowing you
> > down again!
> > Kind regards,
> > Diederick Basson
> Now to gripe again: Please measure the noise; a description helps, but
> semi-quantitative information helps more. Simply run a spectrum -
> CoolEdit / Audition offers it and it's likely to be in your preferred
> audio editor as well. Since the razor buzz makes it sound like a
> power-line noise and I gather you have 50-Hz power, look for harmonics
> of 50 Hz. Any substantial 50-Hz component means one sort of ground
> problem; substantial 100-Hz means filter problems on a full-wave power
> supply; low components there but large ones at higher harmonics makes it
> likely that radiation is the culprit rather than conduction.
> Card sensitivity to conduction and to radiation varies substantially and
> the above is a simplification.
Note that the other likely cause is pickup of the vertical sync signal...
this varies but is usually somewhere between 60 and 80 Hz. An odd
culprit, if you use any, are dimmer-type switches on household
lighting; these create a radiated signal which is "loved" by solid-state