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NAD M51 DAC high-pitched ringing?

Hey guys,

Not sure if I posted this in the right place, but I could use a little help.

Just setting up my new system and I've encountered a major problem: a high pitched ringing. Here's what I've got.

Macbook -> NAD M51 DAC-> Jolida 1501P amp -> Silver SR16 Speakers

Whenever audio is coming out of the computer, through the dac and amp, there's a loud high pitched ringing sound, like after you've been to a loud concert. The ringing comes in and out a bit, but is present about 95% of the time.

When no audio is playing from the computer (music is paused) there is no ringing. But unpause the music, the ringing starts and continues for about two seconds after the music is paused.

I don't think the sound-files are responsible.

So far, I've troubleshooted it and I've hit a dead end:

The DAC plugged into a different amp/speaker setup has no ringing.

When I connect my ipod or laptop directly to the amp: no ringing.

I've also tried using a Ray Samuels Audio Apache as a preamp with the NAD M51 and the Jolida, but there was still ringing.

Interestingly: The RSA preamp has a mute feature, and when the sound-file is playing but the preamp is muted, the music stops but the ringing continues. I don't know how this mute function works, but it does not affect the ringing while the song plays.

Also, if you turn the computer volume all the way down, but keep the song playing, the ringing continues. It does not get louder with an increase of volume on any device.

Other interconnects also don't make a difference, either. I don't think it's power interference, either, but I can't be sure. I've tried different outlets.

I'm definitely a novice and don't know much about the actual workings of DACs and Amps, but the fact that the ringing starts and stops with the music might indicate that the DAC is the problem, but I have no clue exactly how.

So it seems the DAC and the amp are functioning properly independently, but something screwy happens when they are used in conjunction. And the DAC is producing some signal doing its algorithmic thing that the Jolida is picking up on.

Any ideas you guys might have would be a great help. Would contacting these companies be at all useful? Seems like each product works fine individually and they might tell me to buzz off.

Thanks guys,

Charlie
mrcharlienathan
zd542
5,339 posts
 
Here's a few things you can try, but keep in mind, I'm just guessing as to what can be wrong.

Try moving your computer further away from your other components.

Turn off anything in the system that is not being used with you play music. If something is digital like another computer or source, unplug it. Don't just turn it off.

I know you tried different outlets, but make sure you try plugging your computer into an outlet that's not on the same circuit as the rest of your system. You'll probably need to use an extension cord.

Try going Toslink instead of usb to your dac. You'll probably need to get an adapter. They're cheap.

Unplug all usb cords from your computer except for the dac.

This may be some type of gain issue. Your music player software has a volume control, your OS has a volume control and your dac has a volume control, as well. Your dac may even have global gain settings (they may be internal).Play around with some different combinations and see if it effects the noise in any way.

Try a different transport. Anything that has a digital out will work. A cheap cd/dvd player will be fine.

Aside from that, I can't think of anything else. If I do, I'll post again.

bill_k
915 posts
 
Have you tried keeping everything else the same with a different amp? It's possible that the ringing you are hearing when music is playing is due to an issue with the Jolida amp like having microphonic tubes. I would try to eliminate the Jolida to see if the problem persists or not.
mrcharlienathan OP
1 posts
 
thanks for your responses guys, but I still haven't solved the problem.

Moving the computer doesn't seem to affect anything. Everything's unplugged, changed, etc.

When the laptop runs on battery, there is still ringing so I don't think laptop power source makes a difference.

Played around with all the volumes, nothing there seems to make a difference.

To Bill_K: When the DAC is used with a different amp (a pair of Audioengine 2 powered desktop speakers), the ringing stops. But when the Jolida is used from the headphone jack of the computer or from an ipod, there is no ringing either. So each component individually seems to work just fine, both the DAC and the Jolida seem healthy. But something about them working together makes bad mojo.
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