Constant HUM / Denon 3805 with Nait5i

Posted by: jtwurth on 16 May 2005

I have a Denon 3805 for my home theater. I use a Nait5i to power my front channels (Polk LSi 15s). When I listen to music I don't use the Denon and there is no hum. I only get the hum when I power on the Denon. And it does not matter if I'm watching TV or DVDs. the same result.

The real mystery is that before I moved into this house I had the EXACT same setup with only one difference that I've noticed. We had a Denon 2802. We never once experienced the hum. Can anyone help or possibly point me in the right direction toward fixing the problem?

Posted on: 17 May 2005 by andy c

This is an issue with the earhting of the naim amp v the Denon. i had a similar thing with my 2805 into a 282 pre using the unity gain.

I conformed the problem after loads of plugging and unplugging of kit. The earthing issue was caused by the philips LCD tv I have being electrically connected to the denon dvd player (2910), and then that in turn being electrically connected to the 2805.

In the end I cured this by using optical leads between the denon dvd and reciever, and also used the same optical lead between the sky+ and the reciever.

For analogue connections (for CD/DVD-a & sacd) between the dvd player and 2805 i put a ground loop isolater in - and it cured the problem.

Do a search on earth problems - there are quite a few replies on this forum re this topic...

regards

andy c!

Posted on: 17 May 2005 by Tam

I've had this problem too, it's an absolute pain. For me it was caused because the ground for the sky dish is at a different level to the mains ground, hence the loop. I cured it by sticking this box in between my surround sound processor and my pre-amp:

http://www.beststuff.co.uk/xitel_ground_loop_isolator.htm

Basically, what it does is cuts the earth connection between the two components, breaking the loop. This is the same effect as others have achieved by using optical leads (as they have no earth connection).

regards,

Tam

Posted on: 18 May 2005 by Graham Russell

I had this problem too - as reported in another thread in this group.

However, it was fixed last night by using a Chord DIN <-> 4 pin phono cable between my 202 preamp and Yamaha E800 processor. Previously I was using a standard phono cable which caused hum. I'm really confused why the Chord cable worked because the 2 boxes are still connected via the sheild of the cable. I had fully intended to desolder the shield at one end of the cable. I'm a bit confused, but hey it worked so I'm happy

Just a suggestion as an alternative to an opto-isolator (which will degrade sound quality).

Graham

Posted on: 18 May 2005 by jtwurth

Thank you all for all for the suggestions. I will try them out. Since it seems that no one has the perfect solution, I look forward to hearing any other suggestions.

Posted on: 19 May 2005 by David Dever

Please post additional details of your system (additional sources, etc.) or phone us (at NANA) in Chicago.

In a typical Naim system, there exists only one point of contact between the audio ground plane and AC mains earth, typically at the source. As you add sources, this may create loops that cause the problem you describe.