Good guess, it is miniDSP USBStreamer between iOS and RME.
Correct, this is why i mentioned there are cheaper options if you don’t need auto sample rate switching (I need it but many people don’t)
There is a Mutec model supported by HQP but I can’t recall which model. Never used Mutec
You already checked if mc 1.2 is supported?
No idea sorry, never owned Mutec.
Yes, it is the Mutec mc 1.2 (which is discontinued) that is supported by the HQP.
Since it is supported, can I assume that it works reliably?
I don’t know, I never used it. All the input methods I mentioned in this thread, I’ve actually used myself.
UpBoard is supported but still has some quirks.
So you’d need to ask someone that tried it.
I would imagine simple SPDIF to USB conversion is simple though, compared to UAC2
Before you buy anything, do you have an RPi4?
Put RoPieeeXL (free) on RPi4 (supports Airplay1 at 44.1kHz). Then connect micro USB cable between RPi4 and UP Squared. And retry UAC2 input with the settings I previously shared (just for testing purposes to start).
Then use your Zen Stream in NAA output mode connected to your Audiowise SRC.
You need to set HQP OS output mode to NAA backend and select the Zen Stream. Probably also change bits to 24 bits.
I have a feeling this might work ! 
It might even sound better because your Zen Stream will be network isolated your HQP OS.
Qutest’s dual coax input is not galvanically isolated (only it’s USB input is, and optical of course).
Another fixed 44.1k option by-passing UAC2 input is:
WiiM Mini streamer (Airplay2 input, optical output) + miniDSP USBStreamer
You still keep and use the Zen Stream in a better way in my opinion - in NAA mode.
But try the RPi4 if you have one around already. Even RPi3 would work if only outputting 44.1kHz rate but RPi4 is better.
Many thanks for the suggestion.
I don’t have rpi4 or rpi3. I already chose to go for the Upboard.
Zen stream’s NAA is limited to 384, so not bypassing the WTA1 in Qutest. I tried that with HQP desktop. It sounds nice with USB input on Qutest, but I had the same volume issue with SRC-DX when connected to the output of zen stream. To use the NAA on zen stream I don’t need the embedded version and can go for the Desktop version. And instead of buying the Upboard I could buy SOtM sMS-200 neo that supports NAA 768. I liked the idea to not replace the zen stream and at the same time get 768 to the Qutest, via dual BNC instead of USB. For the isolation, I can in the future use other solutions from Audiowise for example. Hopefully, ifi could upgrade/update the zen stream to support 768 NAA some day.
Between rpi4 and Mutec, I would go for the latter.
No worries!
MC-1.2 works, with any input rate to any output rate. But downside is that it always runs everything through an ASRC.
Can you briefly describe the issue you are talking about?
The volume is low when using the SRC-DX at the output to the HQP OS running on the UP squared. However, when I previously tried the HQP embedded installed on a NUC (not the bootable image) and modified the settings for the SRC-DX in alsamixer, the volume was corrected. Can a similar correction be applied to the HQP OS?
It should work the same way, but seems like your SRC-DX is not detected or available. Just in case, first stop HQPlayer service with “systemctl stop hqplayerd” then check the device listing with “aplay -l” and then start “alsamixer” for the correct device. You can then store the changes with “alsactl store” and restart HQPlayer with “systemctl start hqplayerd”.
But best fix would certainly be to have the SRC-DX firmware fixed so that it doesn’t have the unnecessary digital volume control in first place.
Thank you very much Jussi,
I stopped hqplayerd, then entered aplay-l, the screenshot is attached.
How do I start alsamixer for the specific device, such as STC-DX?
I tried to type "alsamixer " but it didn’t open anything. What command should I exactly enter in order to open the alsamixer and adjust the parameters for the SRC-DX?
Thank you for your assistance.
With just “alsamixer” it tries to open card 0. This is card 1, so you need to do “alsamixer -c 1”.
When you retest UAC2 input can you disable auto rate family. Set output to PCM705kHz
And use poly-sinc-gauss (not xla).
@N_FRANCIS Did you get UpSquared UAC2 input to work more reliably now? With those things I suggested to try above
Hi, thanks for the follow up.
I am currently away from home, but tried UAC2 for a little time before. I wanted to report after trying it more. However, here is a quick update:
First, thanks to @jussi_laako, the volume issue on the SRC-DX is now resolved.
Second, I removed the Ubuntu server from internal memory, so cleaned the Up Squared back to factory, and only used the bootable image on the UP Squared.
Third, using UPnP is smooth.
Fourth, using UAC2 with iPhone: setting sample rate and rate limit to 705 and disabling auto rate family, while still using Sinc M, it was possible to play music continuously while switching tracks without hitting stop between the tracks but rather selecting a new track while the previous track still playing, it was smooth without noticeable problems. Once back, I will experiment more and report.
Thank you.
When you test more later, you will have issues with iOS source with those settings you mentioned because iOS will play different sample rates (I assume Apple Music?). sinc-M is integer so you need auto rate family on and rate set to PCM768k. I only suggested different settings for different filter.
With your Zen Streamer though it will all be 44.1k which will be fine with those settings.
The auto family rate and sample rate options matter, depending on filter chosen.
I am limiting Apple Music on iOS to lossless, no hi-res. If iOS output does not include 48khz (like Apple tv which has a fixed 48khz output), so it might be fine, I guess.
