Testing an audio DAC

Hardware Librem 5
21

20250508_164148
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Full source code in minidisc.

Still not full testing as it needed a 600-400 dollar RCA cable for full featuring…

Just tested on Power9 machine and Gnu System and worked very good, the sound is crisp like a concert super-supa detailed.

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I highly doubt that claim.

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It is, a good d.a.c it need a good rca cable too at least. Later it needed too a good AMP, plus good cables and speaker.

A super supa RCA cable will transmit the signal with less resistance and loss. This can translate into more detailed and accurate sound.

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Explain your current and future audio chain in detail and I will find you a more cost-efficient solution.

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I will explain with detail when i get time.

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Also looks like Henry Audio is may change the Dac from AKM to TI-PCM.

Also i still not tested the Henry Audio DA-256(AKM) on Librem 5. = (

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Finally tested Gnu L5_Crimson with Henry Audio DAC, just DO NOT WORK. I guess usb audio is disabled in gnu lnx, but yes enabled things to get work waydroid :enraged_face: , which i will never use it on L5.

bowser-fire-breat8h

Thanks for usb_audio. :enraged_face:

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Nothing changed regarding USB audio in Crimson, you may have just messed something up (unless your device never worked on L5, then feel free to open a MR to enable it in defconfig).

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I not tested in Byzantium, but i think it would be the same behavior, so the DAC has never worked with L5 before.

Thank you.

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I just recently got a Fosi audio ZD3, I will test it with my L5 running Crimson.

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Bought one of these about 5 years ago. Worked great on my desktop, laptops… and even the L5. Of course, after another couple of years, it “schiit” the bed, so I’ve beern DACless ever since. :roll_eyes:

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Yeah I’m just re-entering the hifi thing and of course starting with the chifi stuff, but I’m hoping my experience isn’t the same. Fingers crossed.

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Even if the DAC get worked with L5, still depend on: Bit_Perfect Mode support which i not sure how real enable it as i not trust on the Mixer.
Android 14 enabled Bit Perfect API.

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Retested today and the DAC Henry Audio worked Out Of the Box! :man_shrugging: but No Bit Perfect.

purism@gnu_os:~/Downloads$ cat /proc/asound/cards
 0 [imxaudiohdmi   ]: imx-audio-hdmi - imx-audio-hdmi
                      imx-audio-hdmi
 1 [L5             ]: simple-card - Librem 5
                      Librem 5
 2 [Modem          ]: simple-card - Modem
                      Modem
 3 [H256           ]: USB-Audio - Henry Audio DA 256
                      Henry Audio DA 256 Henry Audio DA 256 at usb-xhci-hcd.5.auto-1, high speed
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“Bit perfect” is a name of a feature in Android APIs. It has no meaning outside of Android. If you want to, say, stream unmodified DSD payload straight to the DAC, ALSA has supported that for many years now and applications such as mpd make use of that capability automatically.

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I think if you use the usb connection to your DAC you’re getting all the bits your media player is sending.

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Yes ‘Bit Perfect’ is only for Android, what do you think ‘Pure Bit’ mode for PureOS? :grin:

Theoretically, Alsa can do ‘Bit Perfect’ (stream unmodified DSD payload) but in practice i still dont is worked, for example, VLC supports it Bit Perfect, but in my tests it still modifies the bit, as volumen ± still work.

There are 2 types of DACs: Synchronous and Asynchronous, but Asynchronous(Henry Audio) relies heavily on Pure Bits( stream unmodified DSD payload).
Clearly, the GNU mixer still doesnt know what to do with these types of DACs as Synchronous is more ubiquitous…
Even on Android14+ App-Dedicated i still do not get Bit Perfect, as volumen and sample rate still get modified as original track. But whatever on Android, i obsessed with getting Pure Bit on L5, as theoretically is possible… i will today try it…

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Well, are you sure that the content you’re attempting to play is actually DSD? Storing music digitally in non-PCM formats usually makes little sense unless you’re doing niche things with niche formats such as SACD. Even DSD production usually happens in PCM (with exception of analog production that digitizes the output into DSD as the final step, but this mostly applies to digitizing old records).

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Henry Audio do not support any audio format itself, it just play Raw Audio decompressed from the Player. So i not using DSD but FLAC and MP3 for testing. DSD just promoted and demanded the use of perfect bit, but that feature is also possible with any lossy or lossless audio format by just bypassing the mixer or any manipulation of the path to the dac.
I never to have a DSD DACs, but i guess that DSDac is decomprenssing-or-directplay in the DAC it self i guess to security any manipulate on the path.

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Well, any playback of PCM source (such as FLAC or MP3) at 100% software volume, matching sample rate and bit depth is already “bit perfect”. For PCM sources, what you may want to use is hardware mixing, which is something else and has been supported in ALSA for even longer (in fact, it used to be the only supported mode of operation without configuring things like dmix in the past :smiley: )

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