Hi,
Personally I've had over 150 different DAC's and right around the same number of preamps. We import audio products, mostly from Europe and the UK and I get to A/B many different brands. So here's my opinion and again it is just an opinion.
It really comes down to the level of your system and how resolving that system sounds. If you go DAC direct and the DAC is properly designed then it can sound extremely musical but will lean more toward the digital side, sound wise.
When I add a world-class preamp to my system then that takes the system towards the analog side, sound wise. They're very different sounding but I would say if you're looking for a highly resolving system then a high quality preamp is an absolute must. The one component I couldn't live without is my preamp.
It really comes down to the preamp and capability that the preamp has to improve your system. There is an old saying that I firmly believe in audio "you don't know what you don't know" and until you have tested this theory with several different preamp then it's impossible to know the correct answer.
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