Written by Paul McGowan
In stereo systems of the highest caliber, ensuring proper grounding is critical. Hums, buzzes, ticks and pops can often be avoided by practicing proper, safe, grounding techniques.
One of the worst offenders of good grounding practices is the cable TV provider. If there are any connections between your stereo system and cable TV, you might encounter seriously irritating buzzes that can only be solved in one of two ways.
If you do run into hum problems when your cable TV is in some way connected to your stereo system, if even through an RCA connection to the TV sound, you can always disconnect the third wire ground of your power amp with an AC cheater plug to eliminate the problem. But that’s not always the best way to go. In fact, there would be many that argue it’s not a good way to go at all; less safe than following the rules.
The alternative solution is to disconnect the ground from the cable TV, but to do that you’ll need an isolation transformer. You can purchase an inline version
for less than $10. Place this in series with your cable TV and the hum in your system will stop. If you want the finest solution out there, you’ll need to pony up a few bucks. Jensen Transformers makes the Cadillac of them all, known as an IsoMax, and is available here
Using any one of these video transformers disconnects ground and galvanically isolates your stereo system from ground nasties provided by your friendly
cable company. Don't bother contacting them for help unless you're in an unusual area of the country. Studies have indicated cable companies score lowest on customer satisfaction surveys, lower even than airlines whose customer service people are rumored to still wear clip on ties so they’re not jerked over the counter by some irate customer.
Here’s some bottom line tips you can use for best grounding practices.
Star grounds are best. A star ground is a collection of grounds all meeting at the same point in a system. Most well designed audio equipment utilizes star grounding internally, but when you hook together products as a system, it’s best to try and utilize one ground point if possible.
Dedicated AC lines form star grounds. In the PS Audio Music Room we have multiple grounded AC receptacles on dedicated lines. That means that each AC receptacle has its own wires running back to the central breaker box where the main ground is also located. If each piece of gear is plugged into its own dedicated outlet, then you’ve formed a star ground.
Plug equipment into a common plug group. A Power Plant, a power conditioner, even a well designed power strip all share a common ground. This helps keep everything on the same ground potential.
- If you’re really dedicated, run a separate earth ground. Not for the faint of heart, but if you’ve a dedicated room, it’s good to have a dedicated ground stake tying it all to one point in a special conductive slurry pit, using exothermic welding bonds and so forth. Best to hire an electrician for this operation, because you want to be safe. You can refer your electrician to this document for guidance.
- If you're interested in a very technical and expert explanation on the subject, Bill Whitlock, president of Jensen Transformers, published an excellent article you can download here.