Roon endpoint (WiFi to SPDIF or USB)

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Expecting a THX AAA 789 this week, and I'm planning to replace the SMSL SH-8 connected XLR balanced to an SU-8. The SH-8 is driving my HD700s balanced using a third party HP cable (the 789 will be a drop in replacement for the SH-8). I created a Roon endpoint by connecting a Chromecast Audio optical SPDIF to the SU-8. I have no criticism of this current setup, but thought the 789 would be worth a try. I like the EQ in the SH-8 and boost treble/bass about 3 dB for the HD700s. I may find I miss the EQ not present in the 789. I am curious if anyone has found another way to turn the SU-8 into a Roon endpoint, the Chromecast seems to work well and is fully supported, but at $40 I have to wonder about error rates and jitter. Anyone else find a good way to Roon the SU-8 (not in range of the Server USB unfortunately) ?
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Citylights
4
Jan 2, 2020
Nowhere as cheap as the Chromecast Audio but something along the lines of the Pro-ject Stream Box S2 Ultra will work wonders. USB out into SU-8.
quezaltrogon
3
Jan 2, 2020
thanks for recommendation. The Pro-ject SB S2 Ultra is just the item I was looking for.... At $849 (AA) it is pricey just to get USB to the SU-8, but I'll bet it is far superior to the Chromecast. I wish there was testing that compared the two in terms of jitter/error rates, etc.
Citylights
4
Jan 3, 2020
More about design: https://youtu.be/7CX-pZRhbtI Purchase from Amazon.de if you want to save a couple of hundred bucks. (Not sure what your import tax will be.) e.g.
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Fayne
2017
Jan 2, 2020
@quezaltrogon Use Ropieee. It is a rather slick roon bridge-centric distro for Raspberry Pi. I totally recommend sticking to Raspberry Pi4. At my desk I've got Drop x Grace SDAC-B, Topping DX7s, Drop x Airist R-2R, and SMSL M500 all connected to one, and they all work flawlessly. I'm doing PoE+ (30w) from my Cisco switch to power mine, so I'm primarily ethernet connected, but I've also verified that wifi works perfectly fine. Stay away from Ropieee on Raspberry Pi3, especially if you're ethernet connected. That single usb channel being shared for ethernet and usb... hurts. It does work on wifi, but doesn't have the best performance. I <3 Roon.
SpeleoFool
610
Jan 4, 2020
Isochronous mode is just one way to transmit audio over USB, though it is the “vanilla” method for generic “audio devices.” Much like the Red Book CD standard, the presumption is that some data loss is OK as long as the stream keeps going. So if you have a scratched CD you get a click, but the song keeps playing. The lack of error correction on CD streams makes it a pain to extract bit-perfect audio, but it is possible (I used an app called dBpowerAmp to convert my CD collection to FLAC). Anyway, if you have a generic “audio device” like a microphone for voice chat, then isochronous transfer is perfectly fine (it’s OK if you get some data loss as long as the conversation is audible and the mic stays connected). But if you’re a neurotic audiophile trying to ensure you get every last bit of your HiRes audio stream into your DAC, then you should use a more robust method. As I mentioned before, I haven’t seen the exact protocols for a DAC-mastered “pull” of audio data, but I do know that isochronous transfers are mastered by the host (they’re part of the USB standard). Therefore, if a DAC is mastering the data pull, then it’s not the standard isochronous push, so there’s at least an *opportunity* to implement data correction. Given the bandwidth capabilities of USB, I can’t see why you wouldn’t want to do that in a high-res DAC. But, of course, that’s not a guarantee that it actually works that way. What I believe most DACs actually do is buffer data coming from the host and issue an ”aynchronous” (on-demand) pull request whenever the. Buffer levels drain to a certain degree. Meanwhile, the buffer directly feeds the DAC circuit as a steady stream. At the end of the day, though, that’s mostly just my own semi-informed conjecture. I do know that the Ayre QB-9, which is still a mainstay in my 2-channel setup, works like that. I believe it was one of the first DACs to do so. The mechanism is described here: https://www.stereophile.com/computeraudio/ayre_acoustics_qb-9_usb_dac/index.html But nowadays I think that’s become a more common strategy since hi-res digital audio is more commonplace and DACs are designed to process much higher-bandwidth audio streams. I don’t know if there are standard protocols for doing this, or if it’s more of a per-device custom thing (USB being a stacked protocol means you can invent your own higher-level exchange mechanisms, much like how ethernet supports TCP/IP, FTP, HTTP, etc.). Anyway, I guess all I can really say with certainty is that the use of USB doesn't preclude the ability to do error correction, but whether it is actually done depends on implementation details.
quezaltrogon
3
Jan 5, 2020
I also used dBPowerAmp to rip my library to FLAC. I like that it validates successful rip with a central database. Thanks for the USB protocol overview. I certainly agree that today, especially with current USB bandwidth, there is no reason that a top-of-the-stack app could not ensure a bit perfect transfer using error detection and correction (or 'packet' resend). I think that by acquiring quality products backed up by objective testing (I'm loving audiosciencereview.com !), one can ensure they're getting so close to the best performance that any better would not result in any detectable improvement (at least to my ears). Wonderful Theater setup you have by the way. I take a similar approach to the things that bring me enjoyment, spend on what matters to oneself (and not having kids helps, I thinks there's plenty of them in any case). I've always appreciated HiFi, and had a McIntosh C20 and a pair of MC-30s with JBLs w/ Phono for many years (70s). Then, for reasons I don't understand, I listened to a crappy system for too long. I've only been back to real "HiFi" since about 5 years ago and I'm loving it. With these latest upgrades I should be set, but maybe another set of headphones, and ?? : ) Enjoy