CDX-2 makes a buzzing noise!
Posted by: Leon di San Marco on 14 November 2015
Hi Naimers!
I have a problem with a CDX-2 MK II. Connected to my QED A240 amp (using a Naim DIN-RCA cable) it makes a terrible buzzing noise. This doesn't happen when connected, with the same cable, to a cheaper Yamaha AX-9 or to a small ifi Nano Headphones amp. Funny enough it doesn't even depend on the QED, since this one works perfectly with my older cd-player, a Traxdata 900. Does anybody have an idea of what's happening here??
Sounds like a ground loop. The Naim CDPs are signal grounded to mains earth. This works well with Naim NACs, but if a non Naim preamp complains about this with a loud buzz, you might need use an interconnect with the ground modified with a series resistance inserted, a so called ground loop breaker when connecting to the troublesome preamp. They exist on Google.
Simon
Thank you, Simon! Do you mean something like this?
Actually I plan to buy a Supernait2…but till then I may need this isolator. And…yeah, I hope the CDX2 won't have the same problem with the SN!
It wont do that with the SNait. Hope will not be needed.
I too suspect its a ground loop, but I would fix or at least ID the problem rather than use a ground loop isolator. But if you re looking to buy a SN, then per ianrobertm & my own experience, it does not happen for sure on a SN so you can buy that without worry.
I suspect the problem might be in the QED amp & possibly a dodgy RCA connection, have you tried connecting to the tuner RCA input.
I am not surprised the Traxdata does not have the problem as that has a 2 wire L&N figure 8 plug - i.e. no earth (ground) connection.
Same with the Yamaha amp, looking at www pictures the captive power cable looks very much like its L&N only.
Finally (to be sure to be sure) have you got a pair of RCA cables you can try to be sure its not a problem with the DIN-RCA.
Hi Leon, this will not be a problem with your SN. Mike above does have a valid idea about possible faulty pre amp connectors.. So worthwhile checking but I suspect unlikely.
A ground loop isolator can often work just by adding a relatively high resistance in series with the ground connection (s). This has minimal impact at reducing the signal level because of the low current flowing with signal, but can be enough to make ground inductance loop too lossy so as not to cause any disruptive induced ac voltage such as from the mains field strength in your house... and that distinctive mains buzzing sound.
Yes, I tried connecting the Naim to the tuner and video RCA input of the QED: same problem. I also tried with a normal pair of RCA cables: it also buzzes. I just wanted to be sure that the CDX2 doesn't have some defect, since I bought it second hand (together with the DIN-RCA cable). But, according to your answers, it's no surprise that a Naim Cd-Player buzzes when connected to some amps, right?
Anyway you're absolutely right: since I'm looking to buy a Supernait2 it doesn't make much sense to work on the QED. My only alternative to the SN was a Unison Research (Unico 150), which, as I hear, blends wonderfully with my Loudspeakers, Duevel Bella Luna. But after the experience with the QED I think I'll stick to the Naim family and get the Supernait.
And by the way, thank you very much for your suggestions!!