Mains Spike Suppression

[Ali Tait]

I've recently started having problems with very loud clicks and pops through the system, not sure why, there have not been any previous problems. I've been trying to sort it out for a while but to no avail, so I decided to fit some mains spike suppression to my pair of Belkin PF30's today in an attempt to fix the problem.

If anyone is having similar problems, take a look at this from the FAQ section of the WD forum, it details what you need and how to do it-

http://www.world-designs.co.uk/forum...read.php?t=149

The parts that are detailed there were either no longer available or not in stock when I looked, so I found these on the Maplin website-

http://www.maplin.co.uk/metallised-p...rdercode=n68cn


http://www.maplin.co.uk/transient-suppressor-mov-499

For each item you want to do, you need two caps and one MOV.

I started by taking the lid off each of the Belkins-



As can be seen, there is no IEC inlet, just a captive lead. The live and neutral are wound around a ferrite ring, and then go to the PCB (The live goes via a 10a miniature breaker mounted on the rear panel) The earth goes to the chassis. See here-



I started by soldering one of the caps to the MOV-



I then crimped some 4mm ring crimps onto the ends of the MOV leads-



Next, I soldered on the second cap that goes between neutral and earth-



I then soldered on a piece of wire on the other side of the cap that will be connected to earth-



Finally, I fitted the finished suppressor into each Belkin-



Before doing all this, I was checking the tightness of the wiring in the mains wall sockets that supply the system as a loose wire can sometimes cause these kinds of problems, and I thought I'd also check the fused switch plate that is mounted next to the sockets as well. This is meant to supply an electric fire but is unused as the house is plenty warm enough with the central heating. I discovered this is a dedicated spur fed from it's own breaker in the CU, so a quick trip to Focus for a single unswitched 13A socket and presto, a dedicated supply for my hi-fi. Bonus!

All is well so far, no pops and clicks, and I swear the system now sounds a little better than it did before.I'm a happy bunny.

The suppressor I've made up here can be fitted to any bit of kit that you may be having problems with, so hopefully the pics will help those not too sure about how to go about it.

Usual caveats apply- DON'T ATTEMPT ANYTHING LIKE THIS UNLESS YOU ARE CONFIDENT YOU CAN DO IT SAFELY,MAINS VOLTAGES WILL KILL YOU!

[DSJR]

I'm amazed that doing this to an already heavily filtered supply box made that much difference, but hey-ho

I always used to suggest dealing with the problem at source, but it's a tricky problem with many causes.

I hope Anthony TD sees this and makes some general comments (please)...

[Reid Malenfant]

I'm amazed that doing this to an already heavily filtered supply box made that much difference, but hey-ho

I always used to suggest dealing with the problem at source, but it's a tricky problem with many causes.

Frankly i'm surprised as well... I know you were taliking about this on another thread Ali, which is where Daves suggestion comes in, treat the source

Inductive loads are the usual problem causers, fridges, freezers etc that cause big voltage spikes when the motor/compressor shuts down. That is where the MOV needs to be for maximum suppression

[Ali Tait]

Yep, I'm well aware of the causes, though I haven't been able to pin it down to anything in the house. It's been several hours now with not one single pop or click, so it works a treat, whatever the cause.