Since a change in the linux USB stack in the way to handle duplicate endpoint declarations, the USBpre2 from Sound Devices is no longer recognized as capture device by ALSA, even when full speed USB1 mode is forced (by pressing “Input 1” button at startup on the unit). It is therefore currently impossible to use the unit to record under Linux (only playback is recognized). The USBpre2 has been working flawlessly in full duplex (USB1) for me since purchase (> 5 years). I discovered the bug recently, apparently I’m not the only one :
I contacted sound devices and they (very quickly) responded I should fall back to previous Linux versions and said “We only support use of the USBPre-2 under Windows and Mac OS”. It is sad to read this message from their support while Linux is officially mentioned on product’s webpage and documentation.
Anyway, I purchased this interface partly because it was (and still is) listed as recommended hardware on Ardour webpage. Given the current situation I think it should no longer be listed as such for Linux users.
As discussed elsewhere in the forum the Sonosax SX-M2D2 could be a good replacement for those who are looking for very high quality and linux compatibility (and have the money!).