I tried running a Sony XA7ES CD player direct to McCormack DNA-2DX and didn't like it at all. The music was thin, sterile, hyper-detailed, and lacked "body". Switching back to a Sonic Frontiers Line 2 pre-amp restored timbral richness, deep tight bass, body, naturalness, soundstaging, and was in general much more musical. I will admit that the Sony volume control is probably not very high quality. I like active tube pre-amps with high quality SS amps. Cheers. Craig.
Why a line preamp?
It's been my understanding that the best component is a straight wire. Further, before the the advent of the phono a preamp was not required. All that was needed was a volume control. Now with the reduced usage of the phono we find we must have the line stage preamp. Where's the straight wire philosphy? Why do we need anything more than a volume control and selector switch? Today I connected my McIntosh tuner directly into my amp since the tuner does have a volume control. It sounded better.