                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.   
