Who is using their DAC as a preamp?

I use my Altair DAC/Streamer and it is my pre-amp too. It is fine.
It is nice.

I've done it for years, started with my Theta DS Pre in the early 1990s, and doing it now with the Cambridge Audio Edge NQ (which also styles  itself a DAC/preamp).  I've never bought the claims that introducing a preamp improves the sound, unless it provides better impedance matching, which is unlikely, or eliminates design problems such as distortion in the gain phase.  I've tried a variety of preamps and the only real difference I noticed was an increased noise floor (that was with a Spectral preamp, not a tube unit, interestingly enough) and some tube bloat.

I use a Wadia 321 DAC and a RP-1 as a pre/phono stage. The RP-1 doesn’t have balanced capability but the Wadia and my amp do. I put the RP-1 in line for the phono stage, which was rated good, and so I could roll some tubes and hopefully warm things up as I my amp is class D. I proly been running the RP-1 and using streaming sources 80% of the time for nearly a year. Just the other day I pulled the RP-1 out of the system and went back to balanced connections from the Wadia to the amp as I been streaming a bunch. I like having both capabilities but wished I could afford an RP-5 with balanced.

ahofer
  I've tried a variety of preamps and the only real difference I noticed was an increased noise floor (that was with a Spectral preamp, not a tube unit, interestingly enough) and some tube bloat.

So true ahofer, that's all they can do, increase noise/distortion/colouration and give tube bloat, against going direct if it's a match, and 99% of the time it is a match.
Many tube preamps aren't a match with low input impedance amps also. 

Cheers George 

I've tried using the following volume-controlled DACs as a preamp: MyTek Brooklyn (with Mojo Audio power supply), MyTek Manhattan II, Berkeley Alpha DAC v1 and v2, Antelope Audio Pure 2, Crane Song Solaris, and a few others whose names escape me at the moment. The only one I have adopted long-term as the preamp in the system is the Solaris. I connect the Bryston BDP-3 streamer to the AES input and the digital output of my tuner to the S/PDIF input. The only downside is that the Solaris has no remote control capability.