|Anthony Grimani (firstname.lastname@example.org) is
president of Performance Media Industries,
with offices in Novato, CA, and Paris, France.
Power conditioning is important, but not
for the reasons you may be led to believe.
For all their esoteric eloquence, power conditioning
companies don’t always
tout the true benefits of their products.
There are several facets of power
conditioning that produce tangible and
valuable results: isolation, noise filtration,
voltage regulation, surge suppression,
and distance monitoring. Each system
that you install needs to have these
components. Sometimes they all come
in one package; other times you’ll need
multiple devices. Cheap products usually
don’t do a very good job, but some very
expensive models don’t either. Compare
specs, ask questions, and evaluate the
responses. If you get numbers and data,
you’re probably on the right track. If it’s
just rhetoric, you may want to look elsewhere.
Good power conditioning begins with the isolation transformer. Its
performance must be better than the 50-100 feet of 10- or 12-gauge
cable between the transformer tap on the pole (or underground) and
your system. This is accomplished by using a transformer with low-output
impedance. It needs to behave like a rock, meaning that the voltage output
is rock solid regardless of the varying current demand.
Speaking of current, the transformer must have enough capacity
to deliver what your system needs. You may choose to drop some less
sensitive power monsters like amplifiers off the transformer to keep its
size and cost down. That’s OK, but the ideal solution is a transformer
that will handle “everything.” Unfortunately, “everything” is a little
vague; it could be either the maximum draw possible from the system
(which is unlikely to ever happen) or the typical draw during normal
operation. It’s your call which to use based on the situation and budget.
Don’t forget to include the power factor. If you don’t know what that is,
I highly recommend that you consult an electrical engineer to help with
your power calculations.
|Introduced in 2011, SurgeX’s XU315-DC is an online 1500 VA double conversion UPS/surge
The transformer can also act as a noise filter. It’s possible to do this
without filter caps; the transformer itself can be an inductive low-pass filter
above 1 kHz. Some methods work better than others. One manufacturer
published an experiment using an oscilloscope on the line to compare
residual noise with different products filtering it. Some let only a few mV
through, while others were up in the 100s. It’s unproven if that noise is
audible when it gets inside audio gear, but it can definitely cause errors in
the sensitive microprocessors of automation systems. Ever wondered why
automated lights go on and off with no bidding? It could be the power.
Check noise rejection specs, and choose the highest values.
Regardless of swings up and down in the input voltage, the output voltage
stays the same. There are a number of ways to accomplish this. One
method is to use a motorized transformer. This tends to be slow and rather
inefficient. Another way involves switching between multiple taps a few
volts apart. The more sophisticated switching supplies use advanced crossfade
techniques to ensure that there are no transients when the supply
changes. The important thing to remember is that slow response is bad,
but so are fast snaps on the line.
Surge suppression basically means lightning strike filtration. Nobody
really cares about a surge from 115V to 125V. Lightning is an entirely
different matter. It ruins gear and leads to hours and hours of testing and
replacing. The key factors to look for in surge suppressors are the response
time (faster is obviously better) and how the spike is routed to ground.
You want all of that high-voltage spike to end up in the ground, not your
equipment. Again, there are better and worse ways to do this. Look for
propaganda and evaluate effectiveness.
Some products provide internet-based distance monitoring. That
means that you can get warnings of problems with power without leaving
your office, and that you can log into the conditioner and monitor the
client’s voltage conditions. You can even do a reboot of the gear from
Good power conditioning may subtly improve sound and picture by
reducing noise and eliminating some potential for ground loops, but I
can’t promise it’s going to be a revelation in quality like the manufacturers
claim. However, it will make all your systems run more reliably and last
longer. That is where the true value lies. In addition to adding $10K or
so in equipment, you’ll have fewer service calls and less gear to replace.
With their systems up and running all the time, your clients will be happy
and stop bugging you, so you can get to that massive pile of work stacking
up on your desk.
Chase Walton contributed to this column.