Which DAC - Streamer or Preamp?

@glennewdick  Agreed the DA2 is a big improvement over the DA1 module, but just because it’s better doesn’t mean its sound characteristics match the sonic preferences of the OP, which brings me back to finding an external DAC that does exhibit the sound characteristics the OP is looking for rather than being committed to whatever the sound is on the DA2 that may or may not be optimal for the OP.  Again, DACs are very personal and the odds the DA2 just magically happens to be an optimal match for the OP versus other options is slim to none, and I don’t know but I’d guess the DA2 upgrade is not all that cheap either. 

I thought about jumping to the A8 right away, but its an upwardly slippery slope

If it was me I wouldn’t do that — I’d get a separate DAC to use with the A6. DACs are a personal choice and sound different, and what are the odds that the DAC in the A8 is best for your particular sonic preferences? I’d say very low. There are tons of excellent DACs out there today so worth doing some research to find the one that best matches your sonic preferences and do that. I don’t believe there’s much difference in streaming between the A8 and A6, and the A6 should be fine as a streamer for now. Or maybe you’ll get lucky and be very happy with what you already have.  Just my $0.02 FWIW.

I believe there are two versions of the Mac DAC cards, call them DAC 1 and DAC 2  — forget what they’re actually called.  The first version is not very highly regarded and the DAC2 was apparently a big improvement.  You might want to check which DAC version is in your C-47 just to know.  The DAC in the A6 is probably nothing all that special, which is why they significantly upgraded it in the A8.  This is just some background info fyi in case it might be interesting/helpful in some way, and obviously your ears always need to be the final arbiter.  Congrats (or condolences) on entering the morass that is high-end audio.