I haven't tested the 8330, but I have tested digital vs analogue for my 8351b, and the difference is completely inaudible, so it would surprise me if the 8330 were different. The d to a or a to d conversion needs to be especially bad to make any difference at all(even the $9 apple dongle is audibly perfect), and even more terrible to make an appreciable difference.
What about hiss? I have heard, at least on the 8330, that the hiss is noticeably quieter when using all digital instead of going analogue.
While I am at it, does turning down the input sensitivity via GLM also reduce the hiss like it does on say, a Neumann? Trying to see if I can get Gens to work for me, as I found the 8030c hiss offensive, and if I can bring it down using the 8330 and GLM then I could work with this.