14 comments
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inonoob Hey
My Rotel Dac plays over coaxial 192 kHz 24bit but over Optical he won't. I read somewhere that Toslink is limited to 96 kHz and to 20 bit.
Can someone confirm ?
Inonoob
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HiFiBerry team @Vaclav: You need to enable higher sample rates in the expert settings.
@inonoob: Many DACs are limited to 96kHz over SPDIF. While 192kHz works with some, it wasn't designed for this. Even if it works, jitter is quite high on 192kHz optical, therefore electrical connection is preferable.
Best regards
Daniel -
Cloth Ears I have a similar problem which may or may not be related. I have an RPI2 Model B 1GB with Hifiberry Digi+ with transformer which is connected using a coaxial cable to the DAC input of my AV amp. I know that the cable and DAC are capable of playing 24/192 FLAC files from my Simple Audio Roomplayer+. However, I cannot play 24/192 FLACs successfully with either Rune Audio or Volumio using the Digi driver supplied with each. If I listen on headphones connected directly to the RP (without the Digi driver selected) then 24/192 FLACs play fine: no skipping, clicking, popping, etc.
I have excluded the RP itself, the cable and the DAC as the root of the problem, so that leaves just the Digi+ board or the software. Has any body managed to successfully play 24/192 FLACs with this combination of hardware and software? What other ways might I try to figure out whether it's a hardware or software issue?
Many thanks,
Cloth Ears
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HiFiBerry team A lot of people are using 192kHz playback with the Digi. Do you have this problem only with 192kHz files?
BTW: If you listen through the onboard output, the music is downsampled as the onboard sound does not support 192kHz.Best regards
Daniel -
Cloth Ears Hi Daniel
It's only a problem with 192 kHz playback with the Digi+. All other sampling frequencies and bit depths work just fine. Could it have anything to do with the isolating transformer on my Digi+ board?
Thanks for the clarification about the down-sampling with the RP on-board sound.
Many thanks,
Cloth Ears
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HiFiBerry team The transformer work also at 192kHz. As I don't know your specific DAC, it is hard to impossible to say why it isn't working with it. Grounding of the Raspberry Pi can be an issue if the DAC input itself isn't grounded but decoupled by an transformer. What DAC are you using it with?
Best regards
Daniel -
Cloth Ears The Raspberry Pi is not grounded. It is powered using a BlackBerry PlayBook charger (5V/2A) which is not grounded. The Digi+ board is connected using a good quality coax cable into an Arcam Solo Movie 2.1 AV amp (http://www.arcam.co.uk/products,solomovie21.htm). The SPDIF input on the amp plays 24/192 FLACs without any problems when connected to my Simple Audio Roomplayer+ (http://www.simpleaudio.com/all-products/roomplayer-models/roomplayerplus).
Many thanks,
Cloth Ears
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Cloth Ears To try to isolate the problem to either hardware or software I have booted up my RP into Volumio and have tried to play a sign wave from the command line with sox using the command:
play -r 192000 -n synth 60 sine 1000
but this returns the error message
play FAIL formats: can't open output file `default': snd_pcm_hw_params error: Invalid argument
Can anybody suggest what I'm doing wrong? I took the command directly from another support post on this forum:
http://support.hifiberry.com/hc/en-us/community/posts/201842861-Digi-Sample-Rate-Issue
Many thanks.
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HiFiBerry team If you run this on Volumio, ther is already a process running that uses the sound card. You need to kill the mpd process first (I'm not sure if Volumio will automatically restart it).
However, the first thing I would look into is grounding. I would also recommend to test the optical connection. While I can't say if your AV amp does support 192kHz via SPDIF, it is worth checking.
Best regards
Daniel -
Cloth Ears Hi Daniel,
Taking your points in reverse order, I know for a fact that my AV amp does support 192 kHz via SPDIF because, as I have already said, that works for playing 24/192 FLACs from my Roomplayer+.
Next, could you explain what you mean by "...the first thing I would look into is grounding." The RP/Digi+ combination is not grounded as the power supply does not have a ground (earth) connection when plugged into the mains power socket. To quote from the user manual for the AV amp "This product is a Class II or double insulated electrical appliance. It has been designed in such a way that it does not require a safety connection to electrical earth." This means that neither the RP/Digi+ combination or the AV amp are grounded (earthed). Might that be a causative factor and what can be done if it is?
Thirdly, I will kill the mpd process and try the tone generation test again. Thanks for the pointer on that.
Finally, I have been able to borrow an older RPi B+ and will try that. Some forum threads have suggested that the B+/Digi+ combination will work even though there are problems with the PRI2/Digi+ combination. Something to do perhaps with differences in the OS kernels for the different processors.
Many thanks for your help with this.
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HiFiBerry team Hi Cloth,
if your Amplifier is not grounded this can be the problem. In this case the shielding of the coupling transformer isn't connected to ground and is free-floating. This can result in signal distortions. The higher the sample rate the bigger the distortions will be. This would explain why you see this problems only at 192kHz. Therefore I would recommend to change the transformer-version by teh standard version of the Digi.
Best regards
Daniel -
Cloth Ears Does that mean that I can return my Digi+ with transformer to HiFiBerry and have it replaced with the standard version? If lack of grounding is an issue, perhaps more needs to be said about grounding in the "Output Transformer" section of the Digi+ description page.
Many thanks.
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HiFiBerry team Yes, you can return it. We will replace it by the standard version and refund the difference.
Best regards
Daniel -
Cloth Ears The standard version arrived yesterday and it works fine playing 24/192 FLACs. Many thanks for your help with this problem.
Hi, I need Your help.
I Have RPI2 with Hifiberry Digi+, latest OSMC and receiver plugged via optial cable. Everything is playing, but ... even I play 192 kHz (24 bit) FLAC file, all I get to the output is 48 kHz. I tried everything I googled, but without any luck.
Can somebody, please, advice me, how to configure device to get RAW PCM (unchanged bitstream) of hi-res audio?
Thank you, Vaclav