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Raspberry Pi USB - some theory?

thetrystero

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The DigiOne or Usbridge may make a difference if you've got a badly designed DAC that's sensitive to jitter in spdif signals or to noise in USB power lines, but a properly designed modern DAC won't be sensitive to either. If you have a look at the Modi 2 review you'll see why Allo picked that one to demonstrate the benefits of the Usbridge - the Modi 2 is sensitive to USB noise like no other DAC tested so far, and gets called out for it. You'll see no such sensitivity on the SU-8 v2 review, so no reason for a Usbridge. SPDIF jitter sensitivity is similarly a solved problem for most DACs now, with the occasional counterexample to show why it's still worth testing.
yes, i emailed allo and they admitted as much. 1db difference. so i'll go with vanilla rpi4 without a transport
 

thetrystero

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The smsl su8 works great with a pi streamer and it sounded so great. I did have an issue with the pair in that the su8 powers down the USB port when you turn on another input (mine did at any rate). This meant that my pi streamer using moode struggled to reconnect with I went back to USB. If you were only going to use USB and not other connections then they will behave well together. I loved the su8 other than that issue. It was bad enough that I moved to a minidsp shd which keeps the USB live. This fully resolved my issue. The pi itself was wonderfully clean with the su8. Transparent even haha.

i will be connecting my tv to the optical input of the su8. so you mean if i use my tv, and later want to use the streamer, i have to power cycle the dac?
 

tw99

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Depending on the software you're going to use on the Pi, there are workarounds for the USB DAC going away and coming back. Picoreplayer, or anything based on Squeezelite, can deal with it for sure.
 

mikeburns

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i will be connecting my tv to the optical input of the su8. so you mean if i use my tv, and later want to use the streamer, i have to power cycle the dac?
I struggled to get mine to reliably reconnect after a power cycle. Your mileage may vary. It was annoying enough for me to sell mine.
 

thetrystero

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I struggled to get mine to reliably reconnect after a power cycle. Your mileage may vary. It was annoying enough for me to sell mine.
What did you end up going with? There aren't many options at that price point for a balanced dac. The newer m300 mkii seems to have issues of its own and is not certain to resolve this issue either.
 

mikeburns

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What did you end up going with? There aren't many options at that price point for a balanced dac. The newer m300 mkii seems to have issues of its own and is not certain to resolve this issue either.
I went with something completely different. I replaced my dac and preamp with a minidsp shd. Have had no connection issues with the USB input and my rpi4, which I had extensively with the su8. Got Dirac and extensive dsp options as well so it really improved my system in alot of ways.
 

thetrystero

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I went with something completely different. I replaced my dac and preamp with a minidsp shd. Have had no connection issues with the USB input and my rpi4, which I had extensively with the su8. Got Dirac and extensive dsp options as well so it really improved my system in alot of ways.
Blimey that thing costs over a thousand bucks . Did you at any point consider the adi-2 fs by any chance? If so why did you go with the minidsp instead?
 

thetrystero

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Depending on the software you're going to use on the Pi, there are workarounds for the USB DAC going away and coming back. Picoreplayer, or anything based on Squeezelite, can deal with it for sure.
Have you had direct experience with this? And it worked without any issues?
 

mikeburns

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Blimey that thing costs over a thousand bucks . Did you at any point consider the adi-2 fs by any chance? If so why did you go with the minidsp instead?
Well... It replaced a fairly good preamp - quad 99. That on the second hand market went for 700 dollars. The sale of the su8 almost got me to a grand, so not much more for the shd. So I guess it wasn't too big of an expense. It brought a transparent dac, streamer, preamp with analog inputs, balanced outputs and Dirac dsp. The Dirac aspect is worth every dollar. It got rid of multiple boxes and improved my system like nothing else really has. The adi was not bringing much more to the table to be honest. The shd is very good value.
 

Bernd

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Hi there, first of all thank you for this excellent site and the forum that goes with it. I would like to submit my configuration to check if anything could be improved in the signal chain and most notably when it comes to the USB connection on the Rasberry. Here we go:

Music Source:
• Spotify via Spotify Connect
• Tidal via Roon
• Flac files stored on my Synology NAS via Bubble UPNP


Streamer:
• Raspberry 4 PI, not extensions, no hats etc.
• Data input via WiFi 5GHz from ISP router,
• Data output via USB (no name cable)
• The power supply is the “ALLO Shanti linear power supply3
• The OS installed is “RoopieXL” (runs as Roon endpoint and Spotify Connect terminal). Note: I have also tried “Volumio” and “Moode” (I did not like the functionality and the sound of “Volumio” at all; “Moode” has the best functionality but does not sound as good as “Roopie XL”


DAC:
• RME ADI DAC FS 2

Headphones :
• Overhead (Focal Clear connected to ADI DAC + minor EQ on the DAC to push bass. BTW: to my ears this headphone produced the most noticable improvement in the overal sound quality - but it was the last addition, so I do not know how it would behave in other configurations).

Do you guys see any room for improvement in the audio signal path???
Thanks for your replies.
Bernd
 

abdo123

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Hi there, first of all thank you for this excellent site and the forum that goes with it. I would like to submit my configuration to check if anything could be improved in the signal chain and most notably when it comes to the USB connection on the Rasberry. Here we go:

Music Source:
• Spotify via Spotify Connect
• Tidal via Roon
• Flac files stored on my Synology NAS via Bubble UPNP


Streamer:
• Raspberry 4 PI, not extensions, no hats etc.
• Data input via WiFi 5GHz from ISP router,
• Data output via USB (no name cable)
• The power supply is the “ALLO Shanti linear power supply3
• The OS installed is “RoopieXL” (runs as Roon endpoint and Spotify Connect terminal). Note: I have also tried “Volumio” and “Moode” (I did not like the functionality and the sound of “Volumio” at all; “Moode” has the best functionality but does not sound as good as “Roopie XL”


DAC:
• RME ADI DAC FS 2

Headphones :
• Overhead (Focal Clear connected to ADI DAC + minor EQ on the DAC to push bass. BTW: to my ears this headphone produced the most noticable improvement in the overal sound quality - but it was the last addition, so I do not know how it would behave in other configurations).

Do you guys see any room for improvement in the audio signal path???
Thanks for your replies.
Bernd

I would sell the Shanti or return it as it is doing nothing at all.
 

Bernd

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I would sell the Shanti or return it as it is doing nothing at all.

Thank you for the fast reply: to be honest - that is really one of the things I have not tried yet. I will switch it to a standard power supply and see what happens. But having been educated by the forum, I fear that you are right - and that nothing will happen. In that case I can just hope, that not too many people follow this forum - because I would not be able to sell it. Tnx
 

somebodyelse

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I suspect there's no actual difference between Volumio, Moode and RopieeeXL too, unless you're using some dsp in one of them. I think they've all been shown capable of passing the RME test file to the DAC unaltered. It seems a good setup. It's no surprise that the headphones would make the most noticable change - we've seen how big the measured variations between headphones are, and the variations between the same headphones on different test fixtures which is similar to the differences caused by different peoples' ears.
 

abdo123

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I suspect there's no actual difference between Volumio, Moode and RopieeeXL too, unless you're using some dsp in one of them. I think they've all been shown capable of passing the RME test file to the DAC unaltered. It seems a good setup. It's no surprise that the headphones would make the most noticable change - we've seen how big the measured variations between headphones are, and the variations between the same headphones on different test fixtures which is similar to the differences caused by different peoples' ears.

I don't know, it is my subjective anecdote but anything that doesn't use Alsamixer sounds colored to me. RoopieXL sounds the best to me.
 

somebodyelse

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I don't know, it is my subjective anecdote but anything that doesn't use Alsamixer sounds colored to me. RoopieXL sounds the best to me.
??? Alsamixer is a terminal gui for changing alsa settings.
 

somebodyelse

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That may depend on their respective configs - both are capable of passing data unaltered, or resampling well or badly. Distro defaults for pulseaudio are usually for convenience not audio quality, and the setting to avoid resampling is relatively recent though. Last I looked (a while ago admittedly) Volumio wasn't using pulseaudio. I've not looked at Moode at that level.
 

Bernd

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Hmm, that is interesting- is there a way to bring up Alsamixer GUI from within RoopieXL??
 

somebodyelse

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I'd expect it to expose the necessary bits already, but I suppose if you're using one of the hats with some controls for low level DAC chip options it might not have them. In that case you'd probably have to ssh in, or somehow install something like amixer-webui. I'm guessing though - it's not a distro I've tried as it used to be Roon-only, but XL might be worth a closer look.
 
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