Top notch integrated vs DAC direct into stereo amp

Forgot to comment about DAC direct into Amps.  Tried this a couple of times, and both times when a good preamp was inserted the sound improved noticeably.  My ONLY source is my DAC and I still will always have a preamp (until I get the Humboldt!!!).  Ken

Audionet describes their Humboldt as Stern + Heisenberg.
That with a great DAC would be killer.  So would the Stern + Heisenbergs.

The Humboldt power is listed as : 
Output Power 2 x 320 W into 8, 2 x 460 W into 4.

The Heisenbergs would be:
Output power:530 W into 8 Ω
1,050 W into 4 Ω
2,100 W into 2 Ω

So the difference in a companies Integrated vs it similar separates is often the power rating, which you may or probably may not need based on your speakers and room.  And you save a pair of (expensive?) interconnects with the integrated, and save considerable space.  Those are the main reasons to consider integrated vs separates, to me.

I do get all that and that is why I went for DAC direct into amp to start.  Just saying in my situation, the preamp improved the sound.

First setup: PS Audio DS DAC into BHK 250 amp.  These are hybrid tube pieces, so maybe that mattered, but inserting the BHK Pre improved sound.  This equipment is now all gone away.

Second: Auralic Vega G2 DAC into Classe CA-2300 Stereo Amp.  Inserting Audionet Pre1 G3 improved sound here also.

I am now upgrading to Audionet Pre G2 and mono Amps, so will be interesting to see which I prefer!

I agree if only one (DAC) input why use a pre...and like to keep things simple..and avoid an interconnect...but my ears will tell me.
Ken