I am curious to know if you can sample from a the digital input, and in
24bits.
And also wether analog audio input samples in true 24bit (not dithered
16bit).

1. I believe you can

2. I know you can't.

because of (2) i've just bought the MP3 blaster USB box, it has phonos
instead of minijacks and is going into the spare tape loop of my amp (now my
tape deck has died). Will report back on performance later! Oh - Ialso have
a Yamaha AP-U70 that I use for recording straight from the SP-DIF out of my
digital mixer - that's a neat piece of kit.

Tim