I've recently bought the PreSonus 1824 and am very happy with it so far.
The other night, I noticed that after shutting down the PC, I was still able to play my keyboard and hear the output through my monitors and headphones. This got me thinking. I thought that perhaps as the device had it's own power, I would just be able to switch on and play without booting the PC up. Sometimes it's nice just to do this if I'm not interested in recording anything.
Sadly though, this doesn't seem to work. Once the interface has been switched off (and subsequently turned back on again later), it seems to lose this ability and will not output anything until the PC is booted up.
Bizarrely though, even though I hear nothing, I can see activity registering on the LED indicators.
Is it possible to set this up via Universal Control? I can't see any reason why it shouldn't be possible in theory at least. It would be a nice little bonus feature.