@52tiger I have an Innous Zenith Mk3. Wonderful DAC. I really felt no need to upgrade other than a strong desire to go explore Lampizator.
@lalitk I'm a tube amp guy and very dedicated to the tube sound. My thoughts: Go SET. So DHT. Of course that means you need very sensitive speakers. I consider the high power push pull tube amps a compromise and often not much if any better than SS. (remember I'm a tube amp buy so I believe tubes are better than ss, not looking to argue that, I respect the opinion of SS guys).
So adding the tube DAC is tubes on top of tubes and I wasn't sure how it would work. I was first attracted to the Golden Atlantic, TRP because I've owned amps that used the same tubes and have a lot of tubes I could roll in. But I graduated from those amps to DHTs like the 2A3 and 300B. I decided to go with DHTs for the Lampizator and avoid buing one and then upgrading later to other, thus the Golden Gate 3.
So I put a pair of EML 300Bs in it when it got here and after just one hour the sound was bigger, more open and airy, and significant more punch. I put in some less expensive PX25s and while still nice, a lot of the sounstage and punch went away.
Long discussion to finally get to the answer to your question, but I'd say if you are going to go with a tube DAC, think about the GG3 as the DHT based DAC that really adds a lot.
Jerry