Problems with Nuraphones DAC

Core Machine (Operating system/System info/Roon build number)

Mac Mini 10.14.6, Roon Server Build 511

Network Details (Including networking gear model/manufacturer and if on WiFi/Ethernet)

RPi in question is on wifi

Audio Devices (Specify what device you’re using and its connection type - USB/HDMI/etc.)

USB DAC embedded in some Nuraphones headphones

Description Of Issue

I have a pair of Nuraphones headphones. As well as being able to use these via an analog connection, they have a built-in DAC that apparently supports 44.1 and 48, 16 bit.

When I plug these into my iMac, Roon plays to them fine. However, when I plug them into a RPi (running Ropiee), I get no audio when playing a 44.1/16 file. If I play an MQA file or some other high-res file, they work fine. Attached are the following screenshots:

  1. Device setup characteristics when connected to Ropieee.
  2. Signal path playing a 16/44 file (no audio, although progress bar shows progress).
  3. Signal path playing an MQA file (works).
  4. Signal path playing a 24/192 file (works).
  5. Device setup characteristics when connected to iMac.
  6. Second part of number 5.
  7. Signal path playing a 16/44 file (works).
  8. Signal path playing a 24/192 file (works).

You’ll see that the setup characteristics differ quite a lot, depending on where the headphones are plugged in. Any help much appreciated.

Hello @Stephen_Dawson,

Thanks for the screenshots. It seems that only 44.1kHz content is affected by this issue, I wonder if perhaps these headphones have an incompatibility with Linux-based endpoints on 44.1kHz?

The easiest solution would be to up-sample all content going through the Ropieee to 48kHz, you can do this by enabling DSP -> Sample Rate Conversion -> Max PCM Rate:

That would essentially up-sample any non-working 44.1kHz to 44kHz.

As for why the native 44.1kHz is not working on Ropieee, maybe this is something that Ropieee author, Harry (@spockfish) might be able to look into?

Hi @noris,

Thanks for looking into this. I’ve already looked at the logs, but everything seems ok.

Then again, your idea of upsampling is an excellent one that I didn’t think of, so I’m curious if this makes a difference @Stephen_Dawson.


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Thanks @spockfish and @noris. Adding upsampling to max rate does indeed work. I believe the Nuraphones upsample everything to 48KHz anyway, so it’s not that big a deal. Incidentally, these 'phones automatically test your hearing (not through the normal tome-playing process, but by actually measuring feedback from the ears themselves) and work amazingly well. I suffer from age-related high frequency hearing loss and these let me enjoy my music again. I could essentially do something myself with Roon DSP by trial and error, and might still do that, but it doesn’t help when listening to vinyl! I’m slightly concerned by putting my vinyl through a digital stage, but it’s better than the alternative of missing out on a lot of the music!

Having said all that, I’d still like to get to the bottom of why 44.1 doesn’t work. Would that be some kind of incompatibility with Linux drivers? And how does Roon know what the max capability actually is, when the Device Setup screens are devoid of any DAC capabilities? Compare that with the screens from a Parasound amp DAC, connected to the same RPi and Ropieee:

I really appreciate the help.

Hi @Stephen_Dawson,

This sounds like it could be a Linux incompatibility, have you reached out to Nuraphone support to see if there are Linux limitations? Since it works on MacOS as expected, this would be my next aspect you should consider investigating.

Roon can request the available formats it support form the DAC by probing for it. Roon tries sending a variety of different format commands and sees which ones the device accepts, but sometimes manual configuration is needed if the device reports it accepts a sample rate when in actuality it doesn’t.

Ok, I’ll talk to the Nuraphone folks, and report back with any findings.

Out of my own interest, how is it that the device characteristics as reported by Roon (in my first post above) vary so much between when the Nuraphones are connected directly to a Mac vs when connected via Linux? There are a lot of things missing in the Linux version, like MQA support, bit depth etc.

Thanks again.

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Hi @Stephen_Dawson,

There are different capabilities based on the driver used. When using Linux, this uses ALSA while your MacOS uses the CoreAudio drivers. Different drivers have different capabilities with Roon.

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