For what it's worth - I had considerable experience using various DAC's with my Veloce tube (battery powered) preamp with great results and every time ( except the last) the preamp added space and refinement to the sound quality. The last time I was using the T+A DAC 200 with the preamp and then took the preamp out of the system and experienced NO loss of sound quality, refinement or control. I agree with Audioman58 - the DAC 200 is VERY special both as a DAC and a preamp. My vinyl (Gold Note phono stage and PSU) also sounds just as wonderful running thru the DAC ( NO conversion- analog in and out, just volume control).
DAC as pre amp
This post is just a brief for posterity sake in regards to the the significance of a good pre. As I have stated in other threads over the last few years , when the subject arise, I occasionally remove my pre from the chain and run my Wadia 321 as the pre. I always find my way back to my dedicated pre. I got some Quad Z-4s awhile back and after a recent post regarding the DAC direct question I decided to try again. This round the improvement was even more dramatic with the dedicated pre and the Quads. My modest system is good enough for my level of listening sophistication. but If I ever decided to upgrade a component in the future , the pre would be the unit I would explore. Another member stated that a good pre will ad a "richness" to the sound. I think that is exactly what I hear.