                PROTECTING YOUR A/V GEAR FROM SPIKES & SURGES

                          Copyright 1993 Dawn Gordon


     Most audiophiles and videophiles spend a great deal of time
designing their A/V systems and media rooms.  From budget components
all the way up to five-figure installations, every aspect of these
systems has been planned with attention to the smallest detail.  While
elements such as color coded wiring and the appropriate cabinet finish
are specifically designed, a very important safeguard is often
neglected, and this can be a very costly omission indeed.  A surge
suppressor should be the final link that ties everything together.

     Mother nature is a very powerful force. Lightening can produce
enough energy to saute every transistor in all the components in your
home, not to mention scramble your brain if you're wearing a good pair
of headphones.  As damaging as Mother nature can be to your favorite
Pioneer laserdisc player, there are other electrical nightmares to
watch for, and they are lurking in the dark just waiting to strike.

THE POWER STRUGGLE

     There are three basic types of power problems you might
encounter. Undervoltages, overvoltages, and noise.  

     Undervoltages are those that fall below the consistent 120 volts
normally supplied by your friendly utility company.  In these cases
either a brownout (dimming of lights) or a full blackout will occur. 
Folks who work with computers usually purchase an uninterruptable
power supply (UPS) to keep their PCs up and running long enough to
shut down their applications.  A/V users can benefit from this type of
protection to prevent their VCR timers from "blacking-out" during a
prolonged power loss, so that important shows can be automatically
recorded in their absence.

     Noise is another type of power anomaly, and it consists of RFI
and/or EMI components.  RFI (Radio Frequency Interference) can be
caused by local radio stations, microwave ovens, cellular phones, and
other sources.  This type of interference can cause audio buzzing and
video distortion in the form of horizontal lines and static. EMI
(Electromagnetic Interference) is often caused by a close
electromagnetic field.  EMI culprits include anything with an electric
motor such as a washing machine or a blender.  EMI noise produces
similar effects to those delivered by RFI. Fortunately, there are line
conditioners on the market that eliminate unwanted RFI and EMI line
noise, most notably from a company called Audio Power Industries. API
models are priced from $229 to $569, and many audiophiles swear by
them, claiming that they really do make a dramatic improvement in the
sound of their systems.

     Overvoltages are the most dangerous of all power anomalies and
they occur when more than the expected voltage comes through your
power line, roof antenna or even through your CATV line and into your
home. Lightening, utility company anomalies, automatic garage openers,
power tools, refrigerators and even florescent lights can cause power
surges. Thankfully, most surges are short-lived, lasting only from a
few nanoseconds to a few milliseconds in length; but don't let this
fool you, a surge or spike can produce over 6500 volts in that period
of time and grill your projection set like shrimp on the barbie.

     The reason surges cause so much damage is because the power
speeds through circuit boards faster than it can be dissipated. This
is where a surge suppressor comes in, and its job is to absorb or
reroute the energy to prevent your THX decoder from turning to toast.

THE SURGE POLICE

     There are basically four different ways to protect gear against
surges.  metal oxide varistors (MOVs), gas tubes, special reactive
circuits, and silicon avalanche diodes.  

     The most popular form of protection is the MOV. MOVs are
inexpensive to produce, and easy to use, as their energy handling
capabilities can be escalated by increasing their size, and using
multiple MOVs in a single box.  The downside is that repeated surge
encounters cause MOVs to degrade.  However, the deterioration is
really very small, and these devices should last for decades.

     Gas tube systems are filled with specialized gases that will arc
over at predictable low voltages.  The internal arc shorts out the
surge.  The only problem here is that a gas tube won't stop a surge
until the voltage reaches two to four times the tube's actual rating.

     Silicon avalanche diodes switch on and act as conductors to
remove extra voltage.  These devices act very quickly, but do not have
high power handling capability.

     Many good surge suppressor use some of the above technologies
together in different stages to accomplish the difficult task of
stopping a surge before it does damage to expensive components.

     No matter how well a surge suppressor is constructed if it
doesn't protect the coax line entering your TV or VCR then you may be
headed for trouble.  A few brands have coax surge suppression (with RF
inputs and outputs built in), and they are highly recommended for
video applications.

SHOP AROUND

     like most other products, surge suppressor prices will vary a
great deal -- you can pay $5.00 or $500.00, but the relationship
between price and performance may not be a determining factor. There
are good inexpensive models, and overpriced do-nothing boxes.  If you
are shopping for affordable models be sure to look at the Recoton
C1960 ($24.95), as it includes coax surge suppression.  In the audio
department check out the Discwasher SpikeMaster 1618 ($39.95).  It
features RFI and EMI filtering.


     When choosing a surge suppressor make sure that the unit you
select has a UL (Underwriters Laboratories) 1449 listing.  This
listing (always printed on the product and packaging) tells you that
the unit meets the minimum safety requirements for its intended use.

     If you can afford it, buy a unit with a warranty that protects
not only the surge suppressor itself, but also the equipment connected
to it.  Insuring mated gear is a new and very welcome practice, and
it's nice to know that if your Sony CD changer is charred the surge
suppressor manufacturer will pay to replace it.  Of course it's
important to read the fine print on these warranties, as special
grounding, and/or specific hookups may be necessary for the warranty
to be valid.  Panamax makes excellent surge supressors that include a
warranty covering attached components -- the company even makes a line
of products with coax protection and models with specialized grounding
for TVRO use.  Prices run from $89 to $299.

     Finally, if all else fails and a lightning bolt, or raging
mother-in-law with an electric prod manages to do some harm to your
gear, it's always nice to know that your insurance company has you
covered. Many policies these days cover electrical spike damage, or
have special riders or schedules that can be added for additional
coverage.  
