My PORTA CORDA MkIII-USB arrived this morning straight from Jan and I went home at lunch to try it out!
Will do a write-up when the MS-1s arrive, but for now:
Corda --> Zu Mobius --> HD600 seems to be quite an analytical setup but not upleasantly so. It's correcting me on lyrics I had previously misheard and I'm hearing new instruments, throat-clearing in the studio, etc. The clarity and separation of elements is brilliant - you can focus on a particular instrument, the rhythm or vocals and find it very difficult to fault the reproduction.
The amp + 9V battery or separate PSU is perfectly capable of driving the 300-ohm HD600 - something which the Total Bithead isn't - for that reason I wouldn't like to go any further comparing this amp with the TB. I will say that the crossfeed feature of the Corda is probably superior to the TB in that it 'muddies' the sound less, but I'm still not a fan of crossfeed.
I agree with iancraig10 about the volume control - the Zu plug is particularly large and this makes changing the volume even more fiddly - you can just about see a larger knob on the picture of the upcoming Move, but it still looks too close?
Even before burn-in, I can see that the Corda and I are going to get along very well and it will do an excellent job of the task I require of it: to get my MacBook Pro talking nicely with the HD600
