In article , Eiron
wrote:
Arfa Daily wrote:

Secondly, if the computer is within spec regarding its emmissions,
then you would have to question why an expensive amplifier is being
affected to a degree that you can hear, by such a low level of mains
borne noise ?

Could be a high-end amp with capacitors bypassing the psu diodes to
reduce 'diode switching noise' and let through RF - thus creating a
market for special filtered mains cables.

If you use a set of bypass caps on the diodes it has the effect of blocking
any differential mode (Live-Neutral) noise via that route. If properly
referenced to RF ground it will also deal with common mode above ground. In
effect you can use it as part of ensuring all the power wiring is RF
shorted together and to local ground.

It also defines the RF impedance at the relevant points rather than
allowing it to change during each mains cycle and with current demand.

Hence in contrast with the implication of what you write, using such caps
to shunt the diodes can be a very effective way to block/reduce some of the
RF noise, clicks, etc. Provided it is done appropriately, of course.

Slainte,

Jim

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