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what exactly does the allo usbridge do?

thetrystero

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i'm trying to put together a streamer to be connected to the smsl su-8 v2. i had initially thought that it would simply be a affair of getting a raspberry pi 4 and throwing volumio etc on it and i'd be good to go, but as i went down the rabbit hole i'm starting to have doubts that if i don't get more complicated than that my SINAD might suffer. case in point, the allo website (https://allo.com/sparky/usbridge.html) claims that there's noise from the USB and i need some sort of "transport" to solve this issue. it attaches two AP reports, one with rpi+dac and the other with usbridge+dac which i admittedly do not know how to interpret. on the other hand, i've read that the DAC should handle any noise coming out of the RPI just fine. I really don't want to spend $250 and end up with a rube goldberg machine. hopefully someone here can help me make sense of what these NDK and LDOs do exactly, what do the AP measurements say, how they actually help with noise and if after all that does it really even matter when the signal comes out the DAC end?

I will be streaming over flac over Ethernet from my NAS, Spotify from WiFi and TV will go in to the DAC toslink.


EDIT: I'm studying their AP report, is "noise ratio" the number i need to be looking at? that number is -74db out of the schiit modi+rpi and -84 out of the schiit modi+usbridge. granted this is for the rpi3 i believe. so 10db of difference?
 
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tw99

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I think the Modi2 had some USB flaws (there's a review thread on here), so it may not be surprising that there are some differences in measurements with it being fed from a "better" source. With a well designed DAC, you wouldn't expect to see any meaningful difference. Pi4 USB into any well designed DAC will be perfect.
 
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thetrystero

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i sent an email to allo and received this reply:

"You are assuming that THD represents sound quality and in part it does but its not the whole story .
Sorry there is not much advantage in THD using USbrdge Sig.
Regards,
Ioan"

I found this rather cryptic so I asked to clarify what the implications of this for final SQ out of the dac was and received this reply:

"No advantage on THD or rather very small. (1db better)
Sound quality and THD are not corelated after a certain level .
Regards,
Ioan"

Which I didn't find enlightening either.

So the conclusion is that I am pretty confident now to go with vanilla rpi4 without any fancy contraptions in between.
 

Kachda

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i sent an email to allo and received this reply:

"You are assuming that THD represents sound quality and in part it does but its not the whole story .
Sorry there is not much advantage in THD using USbrdge Sig.
Regards,
Ioan"

I found this rather cryptic so I asked to clarify what the implications of this for final SQ out of the dac was and received this reply:

"No advantage on THD or rather very small. (1db better)
Sound quality and THD are not corelated after a certain level .
Regards,
Ioan"

Which I didn't find enlightening either.

So the conclusion is that I am pretty confident now to go with vanilla rpi4 without any fancy contraptions in between.
If they can’t clearly tell you how the sound quality improves with their product, it does not deserve your money
 

Wes

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It must be a bridge to otherness.

An Auto US Bridge would take yo back to yourself.
 

Aldoszx

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If I were you, I wouldn't bother with those fancy bridges.
The USB from RPi is all you need for a good streamer, for any USB connected DAC !
From my point of view, USB bridge to whatever is the same thing as thousand $ cables.

Take an RPi4, a good case, any audio dedicated distro like Volumio, piCorePlayer, M00de, etc and enjoy the music !
 

wwenze

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I always wondered how they can tell whether a unit shipped out of the factory is working or not if they cannot verify the performance by testing.
 

voodooless

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i'm trying to put together a streamer to be connected to the smsl su-8 v2. i had initially thought that it would simply be a affair of getting a raspberry pi 4 and throwing volumio etc on it and i'd be good to go, but as i went down the rabbit hole i'm starting to have doubts that if i don't get more complicated than that my SINAD might suffer.

You can't let it go, can ya.. :facepalm::oops:

I really don't want to spend $250 and end up with a rube goldberg machine. hopefully someone here can help me make sense of what these NDK and LDOs do exactly

Then don't.. Do you know what the "medical grade sealed torodial transformer" does, or the "CPLD clock processor"? It's al in your SMSL already. Why not worry about what you actually already have: a pretty advanced piece of DAC with excellent measurements with no reason to doubt that it will shield you from USB noise.

what do the AP measurements say, how they actually help with noise and if after all that does it really even matter when the signal comes out the DAC end?

They say: "don't buy a crappy DAC and then another device to make it a little bit less crappy"

Just hook up the damn thing already and start listening! I can promise you that it will be dead silent (unless your amp is shit ;) ).
 
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thetrystero

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You can't let it go, can ya.. :facepalm::oops:



Then don't.. Do you know what the "medical grade sealed torodial transformer" does, or the "CPLD clock processor"? It's al in your SMSL already. Why not worry about what you actually already have: a pretty advanced piece of DAC with excellent measurements with no reason to doubt that it will shield you from USB noise.



They say: "don't buy a crappy DAC and then another device to make it a little bit less crappy"

Just hook up the damn thing already and start listening! I can promise you that it will be dead silent (unless your amp is shit ;) ).
haha yes, OCD i'm working on it.
since allo themselves admitted there's essentially no difference (see my previous posts), i'm happy to go with vanilla rpi4.
still, strange that they should market it as a device to combat the purported USB noise, and then reply to say there's no improvement when asked.
 
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thetrystero

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If they can’t clearly tell you how the sound quality improves with their product, it does not deserve your money
exactly my thoughts initially..just wasn't confident enough that i actually saw through the jargon.
 

voodooless

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still, strange that they should market it as a device to combat the purported USB noise, and then reply to say there's no improvement when asked.

Well, the device clearly does what it claims in terms of noise reduction on the USB lines. The question is: does it matter? And in case of any self-respecting DAC, it should not matter! Audio companies can make all kinds of wild claims, without ever having to back any of them up. Often it's borderline criminal.
 

RichT

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Hello all, this is very complicated stuff for sure. I guess it comes down to: does your dac know the difference between usb noise and music. How does the dac know the difference? I have the Allo USBridge myself and to me there is more detail in the music when I use it. When the USBridge is not in line, there are details that are lost. It's a very fine line but I can hear it. Fun stuff for sure. Kind regards, happy holidays
 

voodooless

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Hello all, this is very complicated stuff for sure.
It’s not really. You should try psychology…
I guess it comes down to: does your dac know the difference between usb noise and music. How does the dac know the difference?
It doesn’t know what music is. It’s just a digital signal. There is alway noise on a digital line. This is no issue because the interfaces are designed to handle this without issue. It will not result in any data degradation whatsoever.
I have the Allo USBridge myself and to me there is more detail in the music when I use it. When the USBridge is not in line, there are details that are lost. It's a very fine line but I can hear it. Fun stuff for sure. Kind regards, happy holidays
Uhuh…
 
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RichT

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It’s not really. You should try psychology…

It doesn’t know what music is. It’s just a digital signal. There is alway noise on a digital line. This is no issue because the interfaces are designed to handle this without issue. It will not result in any data degradation whatsoever.
Hi well OK, I'll make an appointment right away. Is it useful to try to remove noise on a digital line? It seems you are saying it makes no difference. We can agree to disagree on that one. Seeya on the way to my appointment, happy holidays
 

voodooless

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We can agree to disagree on that one.
There is no need. You can do an actual unbiased test to see if you can actually spot the difference. I’m pretty sure you’d fail such a test.

BTW, I was actually suggesting to study some psychology, not visit a shrink ;)
 

Phorize

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i'm trying to put together a streamer to be connected to the smsl su-8 v2. i had initially thought that it would simply be a affair of getting a raspberry pi 4 and throwing volumio etc on it and i'd be good to go, but as i went down the rabbit hole i'm starting to have doubts that if i don't get more complicated than that my SINAD might suffer. case in point, the allo website (https://allo.com/sparky/usbridge.html) claims that there's noise from the USB and i need some sort of "transport" to solve this issue. it attaches two AP reports, one with rpi+dac and the other with usbridge+dac which i admittedly do not know how to interpret. on the other hand, i've read that the DAC should handle any noise coming out of the RPI just fine. I really don't want to spend $250 and end up with a rube goldberg machine. hopefully someone here can help me make sense of what these NDK and LDOs do exactly, what do the AP measurements say, how they actually help with noise and if after all that does it really even matter when the signal comes out the DAC end?

I will be streaming over flac over Ethernet from my NAS, Spotify from WiFi and TV will go in to the DAC toslink.


EDIT: I'm studying their AP report, is "noise ratio" the number i need to be looking at? that number is -74db out of the schiit modi+rpi and -84 out of the schiit modi+usbridge. granted this is for the rpi3 i believe. so 10db of difference?
You may find this interesting:

 

RichT

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There is no need. You can do an actual unbiased test to see if you can actually spot the difference. I’m pretty sure you’d fail such a test.

BTW, I was actually suggesting to study some psychology, not visit a shrink ;)
OK I'll cancel my appointment and open a book. I have and there's something there. It's amazing how different recordings can sound very different, the better the equipment and the larger the differences. Thanks for your views
 

RichT

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