Digital noise with DAC Teac UD-H01

[andy.room]

I am experiencing a very annoying digital noise (click, pops and echo) when trying to play 69/24 flacs to my DAC Teac UD-H01 using Raspberry PI with USB output. I experience the same problem using other MPD software. The sound is perfect if I play the same files through the USB of the PC (using Foobar2000). No problems when using Raspberry with 44/16 flacs or Airplay from Ipad. For complete informatin I am using a class 10 8GB SD card in the Raspberry. Anyone can help me?

[ICLlP]

I think you would eliminate this problem if you added a HiFiBerry Digi, not HiFiBerry DAC, to your Pi and then connected to the Teac DAC by coaxial or optical.


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[andy.room]

Thanks for your suggestion. I took a look at HIFIBerry Digi, but it looks a bit to much DIY for my standards (needs soldering connectors). Of course I will buy that if it would be not possible to find any software solution to my noise problem. It looks like the issue is related to the USB driver....does anybody have any idea how to work out some software tweaks to solve this issue?

[Woodhouse]

There is a known problem with that dac. It pops and clicks on any linux at highres files.
I recently applied this patch: http://www.spinics.net/lists/stable/msg49593.html to an O2 joggler kernel ubuntu 12.04. It fixed the problem almost 99%.

If you don't like any diy, then it might be to much to patch the kernel of the runaudio. If you don't mind tinkering then applying that patch to the kernel will help you a lot.

I would also suggest to try the hifiberry. If you find someone who will do the 10 easy solderings for you (10 minutes of work) the you have a splendid solution. I and a friend of mine have compared the hifiberry and the teac, and we can not distill a clear preference for either the one or the other. The hifiberry had a minor edge over the teac, but this is based on a non-scientific first impression approach....

[andy.room]

Would anybody be so kind to tell me the complete path of the kernel's files to be modified, as I wasn't able to find those mentioned in the patch of the previous post. Thanks in advance.

[andy.room]

[Woodhouse]

The most likely persons to help you would be either Simone or ACX

You would need the kernel source, along with possible patches that are applied for runeaudio itself. The kernel itself can be sourced from www.kernel.org. You can find the used version in rune by typing uname -a in a console (logged in through putty) Then you would have to patch the sources with the given patch manually, as the patch is for a different kernel version, so the 2 files that are patched may be a little bit different. Then there is the question whether you could compile the kernel on the pi or on another linux system and if so, you'd also need the .config file from the /boot directory as it contains the current configuration. All in all quite a daunting task, that can be a bit too much when you have no prior Linux kernel knowledge. Best bet may be to ask our Runeaudio devs if they can include this patch in their next release....

[ACX]

We are going to update soon our RuneOS repo on GitHub, where you'll find the configuration file we used to recompile the current kernel, so you could recompile it including the required patch.

[andy.room]

In the end I solved all my problems buying a HiFiBerry Digi board. Sound is now perfect, no more hassle. Thanks to all for your help and suggestions.

[Midnight]

IMHO the best solution for playing high resolution files on a RPi is adding the Hifiberry Digi and connect it to a DAC of choice. Playing the high resolution files over USB DAC causes problems again and again and again, cause ethernet and USB is a shared medium on the RPi.
Another solution might be using the Beaglebone Black with USB DAC (ethernet and USB is not a shared medium there).