Nac 202 and n-sub makes very loud buz

Posted by: Chrissw19 on 01 January 2016

I have an interesting (for me at least) problem. I have a nat 05 and cdx2 connected into a nac 202 /nap 200 (with hi cap and napsc) then n sat / n sub. I can switch the player off without trouble on the sub side but, if I disconnect the CD player plug ( after switching it off), the n-sub produces a loud buz. It means that I cannot actually remove the CD player and still use the sub. Is it maybe a ground/earthing problem?

thanks!

Posted on: 01 January 2016 by Richard Dane

How have you set the signal ground switch on the n-Sub?

Posted on: 01 January 2016 by Chrissw19

Hi Richard, I checked earlier and it was on internal. 

Posted on: 01 January 2016 by Richard Dane

The CD player is the earth reference for the system.  

Have you tried with the earth switched the other way?  You may need to switch it to external and then use an external earth wire to stop the earth buzz/hum.  The n-sub is equipped to cover all situations.

Posted on: 01 January 2016 by Chrissw19

Thanks. To be sure, do you mean I should connect a wire from the earth socket to a radiator for example?

Posted on: 01 January 2016 by Adam Zielinski

Two mor things in addition if I could suggest:

* Is your mains "equipped" with a proper 3rd cable - earth?

* Please check the phasing of cables if using shucko-type plugs. If in the UK - not a problem since plugs can only be inserted one way. But than again - I have seen incorrectly wired cables from big-name supliers.

My point being - if you don't have an earhted AC supply, and your earth is simply connected to a negative, incorrctly phased cables may give you that noise you describe.

The above is quite unlikely, but worth checking nevertheless.

Posted on: 02 January 2016 by Richard Dane

Try the switch the other way first.  However, Adam's post above re. phasing of a shucko plug and whether properly earthed is also most pertinent.

Posted on: 02 January 2016 by Chrissw19

Adam and Richard, thanks for your posts. I'm in the UK with UK plugs so that side should be ok. I'm not sure about the 3rd cable earth but I would assume that if it was missing then I would have had problems before trying to remove the CD player. I will switch the sub earth to external and we'll see what happens.

Posted on: 02 January 2016 by Chrissw19

Hi Richard, I have switched to n sub external earth and disconnected the cd player from the power socket. No more of this huge buzz but there is a now a very distinct hum while it is absolutely silent when the player is connected to the power socket (but switched off and n sub earth switched to internal). Not an easy one!

Posted on: 02 January 2016 by Richard Dane

What is the source when the CD player is disconnected?

Posted on: 02 January 2016 by Chrissw19

I tried with 2 sources. Tuner (nat 05) or aux (the last one on the front panel) via the rca plugs (unitiserve into a small dac).