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RASPDIGI LTE LVDS V2 Streamer I2S LVDS HDMI Allo Kali Reclocker

GentleEars

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I came across an I2S interfaced streamer called RASPDIGI V2 Streamer I2S (linked) at Audiophonics.fr, while searching for an optimal way to stream music to my TOPPING DX7 Pro. It is a combination of Raspberry Pi 3 B+, Allo Kali reclocker, and a I2S to HDMI transport of unidentified manufacture. Is there anyone here who has tried this?

I am aware the pin-layout of HDMI cable for I2S usage varies from one implementation to another. The info says, "To ensure the compatibility of your DAC, we strongly recommend that you check its pinout and clock frequency in th table, HDMI tab I2S Format."

Another I2S option I'm aware of is Ian Canada's FifoPi and either the TransportPi or HDMIpiTransmitter. I like the that there is more transparency and information on the solutions by Ian Canada, but I like the fact RASPDIGI comes in a case.

Are there other advantages/disadvantages to either of these solutions?
 

tw99

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Can't answer your questions, but why not just use the USB input on the DX7? The tests seem to show that works very well.
 
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GentleEars

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I am currently using an old laptop to send music over USB, but its fan is loud, and I am looking for a replacement. I tried my Samsung Galaxy S9 with a USB cable, but sound quality is not as good.

I can go for Allo USBridge Signature, but I2S interface is theoretically superior, and I want to give it a try.
 

tw99

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It's not at all clear that i2s is better than async usb...
 

JoachimStrobel

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I came across an I2S interfaced streamer called RASPDIGI V2 Streamer I2S (linked) at Audiophonics.fr, while searching for an optimal way to stream music to my TOPPING DX7 Pro. It is a combination of Raspberry Pi 3 B+, Allo Kali reclocker, and a I2S to HDMI transport of unidentified manufacture. Is there anyone here who has tried this?

I am aware the pin-layout of HDMI cable for I2S usage varies from one implementation to another. The info says, "To ensure the compatibility of your DAC, we strongly recommend that you check its pinout and clock frequency in th table, HDMI tab I2S Format."

Another I2S option I'm aware of is Ian Canada's FifoPi and either the TransportPi or HDMIpiTransmitter. I like the that there is more transparency and information on the solutions by Ian Canada, but I like the fact RASPDIGI comes in a case.

Are there other advantages/disadvantages to either of these solutions?
Is this 2Channel or MCh?
 
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GentleEars

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It's not at all clear that i2s is better than async usb...

I am not sure of the actual result, but I2S seems a less convoluted way to transport the data to a DAC stage.
 

tw99

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I am not sure of the actual result, but I2S seems a less convoluted way to transport the data to a DAC stage.

There's an article about i2s in the reference section of this site, I suggest reading it.
 
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GentleEars

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There's an article about i2s in the reference section of this site, I suggest reading it.
Do you mean the thread titled "Study: Is I²S interface better for DACs than S/PDIF or USB?"
 

somebodyelse

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Do you mean the thread titled "Study: Is I²S interface better for DACs than S/PDIF or USB?"
I'd guess that's the one @tw99 meant. In short, for a well implemented DAC there won't be a difference in performance between different transport methods so long as both transports can handle the format. A poor implementation can screw up any of them - see the initial D90 results where there were problems with the AES interface implementation, now corrected. The DX7Pro is fine on USB so I'd get a Pi4 or an old thin client and spend the difference on something else.
 
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GentleEars

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I'd guess that's the one @tw99 meant. In short, for a well implemented DAC there won't be a difference in performance between different transport methods so long as both transports can handle the format. A poor implementation can screw up any of them - see the initial D90 results where there were problems with the AES interface implementation, now corrected. The DX7Pro is fine on USB so I'd get a Pi4 or an old thin client and spend the difference on something else.

So you're saying that, DX7 Pro's asynchronous clock recovery on USB input should be good enough that there is little point on reclocking the input on the streamer's side (a la Allo USBridge Signature)? Use Pi4 to get separate bus for Ethernet and USB, just in case? How about a power supply? Should I get an audiophile grade libear power supply? Or will a standard USB supply suffice?

i am no EE. Just trying to be an informed consumer. FYI, my DX7 Pro would be connected to a Hypex NC252MP based stereo amplifier from Audiophonics, and onto my B&W 685 (next to he upgraded).
 

somebodyelse

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The DX7 Pro's excellent test results were on the USB input from a PC running Windows 10. I don't think the other inputs have been tested, but I'd be surprised if they were any better, and there could be an issue like the one with the D90 linked above. The Pi 4 seems to be free of the glitching on USB (although I only ever got that when using BruteFIR, and there were workarounds even then). It's a more capable board all round than the older ones, and barely more expensive, so you're getting some future proofing at essentially no cost. A decent standard USB supply should be fine too - the Pi will probably have more influence on the power going down the USB cable than the power supply. You can always swap it out later if you feel it's a problem.
 
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GentleEars

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The DX7 Pro's excellent test results were on the USB input from a PC running Windows 10. I don't think the other inputs have been tested, but I'd be surprised if they were any better, and there could be an issue like the one with the D90 linked above. The Pi 4 seems to be free of the glitching on USB (although I only ever got that when using BruteFIR, and there were workarounds even then). It's a more capable board all round than the older ones, and barely more expensive, so you're getting some future proofing at essentially no cost. A decent standard USB supply should be fine too - the Pi will probably have more influence on the power going down the USB cable than the power supply. You can always swap it out later if you feel it's a problem.

Thanks for leveling my head. I will start with a simple RPi 4/USB solution. That will save me money, without narrowing my options.

Having said that, I would still like to hear reasoned arguments for reclocked, USB or I2S solutions.
 

sev1

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I am currently using an old laptop to send music over USB, but its fan is loud, and I am looking for a replacement. I tried my Samsung Galaxy S9 with a USB cable, but sound quality is not as good.

I can go for Allo USBridge Signature, but I2S interface is theoretically superior, and I want to give it a try.

Out of curiosity, what software did you use for playback on your S9? Almost all apps send their audio through the Android audio subsystem which resamples everything to 44.1 or 48. USB Audio Player Pro (UAPP) and the Onkyo Software are capable of sending bit perfect audio to your DAC. I'm not saying the S9 is some sublime device but it might be as simple as that. You have to pay to enable the feature on UAPP but its pretty inexpensive and it works great with Tidal and Qobuz as well as local files.
 
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GentleEars

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Hi sev1,
Yes, I've been wondering why the USB output of my Samsung Galaxy S9 is perceptually inferior to that of my Windows 10 PC.
I run the Spotify on the phone feeding the USB port of my DAC via an OTG adapter and a regular USB cable (that came in the box with DX7 Pro), and control it from the Spotify application running on other phones/computers. I know about the UAPP app, but my wife and I enjoy the convenience of the Spotify Connect, and don't have paid subscription to other services like Tidal or Quobuz.
Just yesterday, I bought a Raspberry Pi 4 and set up Raspotify on it. I am able to stream Spotify from it to the DAC, but DX7 Pro reports 48KHz, and the sound quality isn't that good. What do I have to give it higher sampling rate?
 
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GentleEars

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Having written the above, I realize Spotify content is either 44.1KHz or 48Khz, so it's natural DX7 Pro reported 48KHz while decoding a song. FYI, I'm setting Spotify to stream at 320kbps. Maybe, my "perceptual difference" is just that.
I will try a Tidal trial and UAPP to see if my perceived sound quality improves.
 

gvl

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Spotify is 44.1kHz compressed. Resampling is taking place somewhere if you see 48.
 
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