DACs that do well without a preamp

Soekris dac2541. It uses an internal headphone amp as the line driver amp selectable on the front panel. I'm using it to drive an old Threshold amp through a 10k Ohm pot. Works very well. 

Exogal Comet.  Great straight into an amp (no idea how it sounds with their ion amp)

Yet another big vote for the RME ADI-2. It is super in my big tube mono block amps. There’s no turning back and RME sends regular software upgrades. 
 

Just an unbelievable value. 

I'm currently listening to a Marantz HD-DAC1 using the variable output to a Mcintosh MC2100. The 2100 has left and right output gain levels and once calibrated with the Marantz volume control sounds wonderful. 

the rme is a good dac, many features, great value for the $ - it has an upfront and center sound, fairly flat and narrow imaging

the soekris 1541 (predecessor to the current 2541, some believe it is slightly better, but that is a separate conversation) has, to my ear, in my system, a more dimensional, fleshed out sound, much more proper imaging and spatial properties

i think the rme is terrific for headphone listening but less capable in an in room system where the user is trying to use speakers and room acoustics to recreate a realistic stereo image

otoh, the soekris dacs have a headphone output but i have heard some say that it is not the last word in sound quality with harder to drive hp's...  i am not so much a headphone guy so i cannot speak firsthand on this aspect