Protection of audio equipment from AC power anomalies using surge
suppressors has been widely discussed and, because of its importance,
is worth reviewing….
Surge/transient suppression is basically accomplished by the use of
parallel-mode or series-mode devices. Parallel-mode suppressors use
metal-oxide varistors (MOVs) that are effectively in parallel with
the incoming AC supply and the connected equipment. They are
considered “sacrificial” because they are willing to give their
lives to save your equipment. In doing so, however, they usually become damaged and are no longer capable of protecting equipment.
Series-mode suppressors came on the scene and their claim to fame was
superior surge protection with very low “let-thru” voltage and
the ability to withstand numerous 6,000V/3,000A “hits” with NO
damage or degradation. The device that provides this protection is a
reactor (inductor) in series with the AC line supply that opposes
changes in incoming current or voltage. Unfortunately, the reactor
also results in a higher source impedance and connected equipment
(power amps, in particular) can become current-starved during
demanding musical passages. The audible result is reduced dynamics
and bass impact. To counteract this, some companies use capacitor
“banks” to satisfy dynamic current demands. Such capability does
not come cheap and to use one example, the Audioquest Niagra 3000 has
a retail price of $3,000.
The approach used by most audiophiles is to simply run all source
components through the series-mode suppressor and to plug the power
amp (or integrated amp) directly into the wall outlet. This works
well since the power consumption of most source components is very
low with a near-constant current draw.This setup, of course, leaves the power amp unprotected.
The solution to that problem, as mentioned, can get expensive. It may
well be, however, that the current demand of some amps are low enough
that plugging them into the series-mode suppressor has no (or
minimal) effect on sound quality. The only way to determine that is
to try it. For some, a slight degradation in sound is a worthwhile
tradeoff for the protection offered.