[LAU] MotU Ultralite AVB observations.

Getting my Ultralite AVB working on Linux Mint 19.3 has been quite a struggle and I've learnt a few things along the way, which may save others some wondering. Ignore any thoughts of USB power management causing any issue. The device never uses any USB power, as confirmed with an inline USB V/A meter. Firmware more recent than 1.3.2+520 suffers from the 'bitcrusher' effect, where audio can be heard for about 30 seconds, until it fades to junk while appearing on higher number channels, until it does the same again. That firmware is pre Touch Console™. Firmware and release notes in the Ultralite AVB section here: https://motu.com/techsupport/technotes/firmwarechangelog A great deal of good information over at the Linux Musicians forum: https://linuxmusicians.com/viewtopic.php?f=6&t=18046 (Thanks to Eric Schoster for pointing me to that one.) One gem is that it can be set to class compliant mode with: curl --data 'json={"value":"UAC"}' IP address/datastore/host/mode curl --data 'json={"value":"24"}' IP address/datastore/host/maxUSBToHost (Replace "IP address" with its address on your network) Change to its proprietary mode with: curl --data 'json={"value":"USB2"}' IP address/datastore/host/mode curl --data 'json={"value":"64"}' IP address/datastore/host/maxUSBToHost On my current hardware (i7-8700K) the Ultralite takes 27 seconds from first light in the display to showing detail in the display and there's a further 20 second delay before any activity shows up in a terminal window running 'tail -f /var/log/syslog'. There are very many messages like: 'clock source 1 is not valid, cannot use' Yesterday I was seeing 240 of those in blocks of 40, with each block followed by: '[pulseaudio] module-alsa-card.c: Failed to find a working profile.' and etc. Today, after trying the latest firmware, seeing the bitcrusher effect and reverting to 1.3.2+520 again, I only see two complete blocks and the reporting stops about half way through the third block. Qjackctl will then start the server, on either hw:AVB or hw:AVB,0. It always seems to need changing to the one of those it isn't set to. :) I can only think that my dual booting and using it on Windows 10 caused the trouble I was seeing when using it on Linux afterwards. I still can't use anything which isn't 'jack aware', but I can live with that, for now. VLC offers 13 'Ultralite AVB, USB Audio' devices to chose from, including "Direct sample snooping device". Linux, generally, doesn't seem to maintain an optical output if a player app stops playing... -- John.