First post people - wondered if anyone could help. Long story short - doing some DIY plugged a hand drill into a socket (not the same room as Hifi but on the same ring main DOH!), anyway in hindsight I know I shouldn't have but didn't think , anyway I always leave my system left on standby and shortly after went to listen to a CD. Although music reproduction is normal, volume etc.. it is now accommpanied by a high pitch buzz - not great for SQ lol. I have my own ideas - but any other views would be much appreciated. System consists of CD transport, DAC, pre amp, 2xmonoblocks, speakers and sub. Thanks.