AV2, unity gain, and mains pops and clicks

Posted by: Mark R on 15 October 2005

I've recently become a (rather pleased) AV2 owner. The AV2 fronts go into the AV input on a 282, which is set to unity gain. The AV2 and 282/SuperCap are running off the same Graham's Hydra into a single mains socket. With unity gain set, the pops and clicks on the mains e.g. fridges turning on/off, etc., can be alarmingly noisy. CD and tuner inputs do not exhibit this noisiness. Turning off unity gain returns the AV input to the same level of noise as the CD and tuner inputs, where only the worst of the pops and clicks make it through.

A brief search of the forums produced threads discussing hum and unity gain; I am not noticing this on my setup to any great degree, and do not know if the two situations are related.

Is this a unity gain "fact of life", or is there something that can be done to cure the pop/click exposure?

Thanks,
Mark.
Posted on: 16 October 2005 by Steve2701
Mark,
We are not allowed to discuss in detail what can be done with mains (See the rules) but you can help eliminate your problem by having a completely seperate spur for your system.. even better get a completely seperate consumer unit a & supply from the meter. It is well worth the effort. This, by law, must now be done by a qualified electrician who will issue a certificate when finished for your insurance / house sale folder.
A search on mains / spurs on the forum will give you a good starting point.
Posted on: 16 October 2005 by Adam Meredith
Also - if the problem has an obvious source - look to local solutions (filtering the problem - rather than the hi-fi) and/or service the faulty unit.
Posted on: 16 October 2005 by Mark R
Many thanks for replies. Unfortunately, my flat is rented, so a separate spur is not possible. The mains noise is certainly more frequent in this flat than I've experienced before, but is only noticeable when using unity gain. Any switching can cause it, to varying degrees. For example, I can trigger it by switching the lights on and off. Dishwashers, fridges, you name it, they come through, so finding a single fault point may prove difficult. I can certainly live with it, but am trying to understand why unity gain appears to expose these noises far more than other settings.
Posted on: 16 October 2005 by Trevor
The problems I had with noise using the AV2 with Unity gain on the Pre-amp were because of a long lead connecting the AV2 to Pre-amp some 4-5 meters. This was over come by fitting low value resistors in the connecting lead.
Posted on: 17 October 2005 by Adam Meredith
It may well be that the solution above, fitting padding resistors to the interconnect lead, will get rid of your problem.

Please contact your dealer to arrange or investigate.
Posted on: 17 October 2005 by Mark R
Trevor, Adam - thank you. I have the standard reverse interconnect between AV2 and 282, but do have 4m interconnects from satellite box and dvd player into AV2. Will contact dealer.