Humming noise

Hello,

My AV2 is around 5 meters from the rest of my kit. I made up a 5m long cable like the old grey Snaic lead to the 552 for the AV input. When first used there was a background noise like a radio with no aerial connected. It was suggested fitting 2 x 22ohm padding resistors at the AV2 end of the lead. This got rid of the background noise completly.

Is your AV2 turned on ?

I find all on and the BR not on stand by and it's all quiet.

A hum sounds like a ground loop. Does it go away if you unplug all your other components apart from the AV2?

Does the AV2 have a switchable chassis/float switch to isolate the signal path from ground?

If you unplug your TV Ariel does it go away?

Good point. When I lived in a flat, the distribution system was causing a hum in my system. I had to hand build a cable that only connected the shield at one end to be rid of it.

You weren't watching a World Cup game, by any chance?

quote:

Originally posted by graham55:
You weren't watching a World Cup game, by any chance?

Good one

Gerald,

first of all you need to establish it isn't an earth loop. TVs, cable TV systems etc.. are notorious for this. If you unplug TVs, DVDs etc from the AV2 does the hum disappear? Plenty of threads on here explaining ways of curing this.

Apart from that, the AV2 will have some difficulty driving a long cable. Naim recommend padding the cable if 3m or longer. They can supply this or else contact Steve Hopkins at customer service for the correct value.

thanks guys , i will check all this and report back

weird - tested now and it was fine but was really humming later on in the previous few evenings. Could it be a mains issue ? rest of the kit quiet apart from a noisy 145 thats always made an audible humm (maybe is should get it looked at by naim or borrow another to see whats what). I spoke to James at Tom Tom whose ordering me a new 3m cable , hopefully it will come as you mentioned Richard and that will remedy it.

Graham your reply made me laugh

I had a very similar problem with the left and right channels from my stereo with the AV2 being about 5 metres away. When switch on from cold it was quiete for about 30-40 mins then the noise came back. After numerous discussions with naim i asked about a mains cleaner (which they don't normally recommend) but they said if i could get one to try out, give it a go. I bought a monster mains cleaner HTS1000, i put it in and it was the same, but after about a week all went silent.

since the new cable has come its back to normal. Thanks for the advice guys

Glad it's sorted. A point for the future.

To avoid earth issues with the kit that is connected to my AV2 I only use optical cables. That way the tv, blueray and sky hd box are etectrically isolated from the stereo systems and because of this I have never had earthing issues.