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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
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.
zd542
5,339 posts
 
"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."

"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."

I'm still not sure what the problem is, but reading those quotes made me think of a couple of other things you can try. First is a different music player. I assume you are using iTunes. Try Quodlibet for Mac. Its open source, so there's no charge for it. I can't say for sure, but you'll probably like it better anyway. It plays more formats and is a much better tagger than iTunes. Second is, how are you connecting your Mac to your dac? To get digital output, you an only do it 2 ways; usb or Toslink using a special adapter that plugs into your headphone jack. I'm assuming usb because its the most popular option, but a lot of people do use the Toslink option. And third, how do you connect your dac to your to the Jolida? This is really important because you have a balanced dac while the integrated is single ended. Even if you are going SE out on the M51 to SE in on the Jolida, you may have to do something to your M51 to make it work properly in SE mode. If you are using balanced cables and adaptors you still need to be very careful. Not all IC that have XLR connectors are balanced. Internally, the cables may be SE. There's a lot of confusion on this because when most people see IC's with XLR connectors, they automatically assume they're balanced. That's not always the case.

It also wouldn't be a bad idea to call NAD. Its very possible that you're not the first person to have this problem.
georgehifi's avatar
georgehifi
10,312 posts
 

Has anyone bothered to see what happens after 20khz to the M51,s FR? Very strange for a dac or cdp, looks like the resonance of early metal dome tweeters.
Have a look at the second graph and look what happens after 20khz up to 100khz. Ultra sonic noise? could be upsetting the Jolida?

http://www.stereophile.com/content/nad-m51-direct-digital-da-converter-measurements

Cheers George
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