Are streamers digitally enhanced?

Another important difference between streamers not mentioned thus far is operating systems employed. Various OS have potential to affect sound quality via optimization of hardware, this means optimization via minimizing noise and/or providing low latency, this means speed or efficiency of sending data packets. There are many technical explanations for why streamers don't all sound alike, read some white papers over at Audiophilesyle forum to educate yourself.

It would be illustrative if someone or some outfit like the venerated or hated depending on your views, like ASR, could take a streamer, feed it a known series of data and then simply measure the digital output to see how accurate that output really is. 

Obviously, things like jitter, if the measuring equipment is good enough to discern it, can play a part too in how we perceive the quality of that output.  But do you REALLY want to know the truth, or would you rather be happy in simply accepting that you think one streamer sounds better than another feeding the same external DAC via the same digital input? 

Like the old Star Trek episode goes, "Is there in truth, no beauty?" or as John Keats put it, "truth is beauty, and beauty is truth". But you might prefer your beautiful girlfriend with a little makeup on. 

All I know is I went from a 1K streamer to a 6K+  streamer and the difference in sound is palpable.

To put a coda on this discussion, I spent an hour with Gemini as an EE professor, explaining the fine points of digital streamer design. It confirmed the primary of clock and PSU, but also mentioned another variable. 

FLAC is a lossless but still digitally compressed file that has to be converted to PCM and the quality of that conversion depends on both hardware and software. The lower tier of streamers use off the shelf computer versions, while higher end ones use specific chips and in-house specialized software to do the most bit perfect translation. 

Apparently few audiophiles are curious about the technology underlying digital sound. We'll go on for hours about tube types, but chips and software are somehow uninteresting. Personally, I find all aspects of audio technology fascinating. 

@mashif I, for one, learned something from the discussion, especially from your Coda above. I would only add that some manufacturers, like Auralic in my experience, will give the user the option of adding DSP functionality through configuration software options. Whether or not the default configuration also includes such optimization is still an open question for me.