Taking a break from the transportable rig during the lockdown and focusing solely on Mojo portable rig:
I got it to near 'mini-DAVE' desktop levels so it's stable (subjective opinion of course). After spending time in the Chord Summit-Fi threads helps one to find out optimal solutions for their Chord everyman devices and learn that digital source matters big time. During the prototype testing phase, I couldn't explain the sound difference and attributed it to some type of magical synergy. Recently, some posters with similar digital sources and I came to the conclusion that it's PrAT. By optimising your digital source, the music becomes much more controlled, slows a bit and gives the music room to breathe. Redbook files sound like HiRez. Adding a mScaler is known to have a similar effect. But bottom like, PrAT is amazing with the right digital source. It's my #1 factor now when considering a digital source. My past considerations for changing source was to be 100% EMI/RFI-free, off-grid battery portable use and purity in sound. But after some experience, I consider PrAT to be an big X-factor. PrAT didn't even cross my mind once as a decision factor when choosing a digital source. It's amazing how different music sounds with the right pacing and rhythm.
Besides lifting the veil by going glass optical, you maintain the crispness of USB without USB's harshness. Of course your limited to 24/192, but it's okay as I converted back to redbook now after a decade of HiRez listening. The digital source change my listening shift to redbook away from SACDs / HiRez. Tho HiRez still gets some good playtime, but SACD's are too soft so still with anything PCM.
I was fortunate to discover a solution where the PCM data goes from CPU via the i2s bus to the optical decoder then travels via glass optical fiber straight into Chord devices. So no USB audio involvement or some type of USB complicated conversion / USB bus path into optical. So I was able to get my sound purity requirement.
---- Onto Mojo. ----
I was able to pickup a Mojo hours before the holiday sale was over a few months back so have a portable rig again.
I tried a different optical source with Mojo for a few weeks. Couldn't listen anymore and was considering selling. I switched to the digital source I was using for the H2 and was able to replicate the PrAT factor with the Mojo. I can't stop listening now. I think this makes a great budget rig w/ this digital source as you get excellent $2K SQ for about $4-500 minus the optional glass optical cable. I don't know if I could recommend the Mojo without this digital source + glass optical. I almost gave up on the Mojo. Mojo going nowhere now.
You get better depth by going optical, so you get a more 3D sound vs 2D using other inputs.
I am getting rather different sound from coax and USB inputs with the latter sounding better, what’s the reason for this?
It’s complicated and depends upon a number of factors - principally the amount of RF noise injected into the Mojo, and the amount of correlated noise that gets in. It will depend upon the source device as to which sounds best. My preference is optical, as this has the smoothest sound quality and best depth, as it does not suffer from both of the aforementioned problems.
link
---- Onto UE10 ----
Listening out of the UE10 (old skewl neutral monitor) is a wonderful experience now. Ground zero of CIEMs (CIEM0).
Back in 2004 I cracked the shell on my UE Pro 10 and only recently got around to re-shelling a few years ago (no re-shelling available in the early days). It's now being utilised (~600 hours usage) with the Mojo.
Most will probably not recognise this HF legend, but it's someone I highly respected on this site. I was looking at old impressions not for nostalgia but I'm putting the UE-10 through it's paces now:
Really enjoying this UE-10 classic with Mojo...
---- Misc ----
With Squeezebox 8 on the backend and iPeng on the frontend, it's lightning fast even tho wireless.
http://antipodes.audio/squeezebox/
https://apps.apple.com/us/app/ipeng/id767266886
Music sources for testing:
http://www.thetargetcdcollection.com/p/target-cd-info.html
Master sources before sound processing was a thing....
---- Note ----
You can also convert your beloved USB DAC into a DAP w/ wireless UI via smartphone. The power will be fed from battery pack -> RPi -> USB DAC (Dragonfly, Fulla 2, Soundblaster G6, etc.). As long as it's a low req power USB DAC. Just change output to USB Audio. I don't recommend USB Audio for SQ but it's a fair compromise if you want to use your fav USB DAC OTG.