How does the Cambridge Azur 840C sound compared

I have had both units in my system. I went with the Sony. Warmth was the key factor. Trying both units in your system is the only way to tell what is best for your ears. After doing the latter, if it is about equal, I would go with Sony in that the service/warranty if much better.

After trying a lot of units including the 840C, I too kept the Sony 5400. I found the 840C a little lean and lacking punch (most noticable on bombastic classical or rock recordings) but otherwise a very fine sounding unit. The 5400 does everything well. The Bryston BCD-1 was the only unit that beat the Sony IMO, it offers the best you are there imaging I've heard under $2500. The Sony of course, plays SACDs and it plays them quite well.

I've only heard the 840C in a friend's system, which is very different from mine (I have Thiel 3.6s, Quicksilver 90 watt monos, and Quicksilver Linestage). As such, I cannot really comment on how it compares to the 5400, which I have owned for about a week now.

My frame of reference is the Rega Saturn I owned for a couple of years prior to the Sony. I recently opted to go with the 5400, mostly because I wanted a player that would do SACD. I am aware the Sony supposedly requires a long break-in time; I got mine lightly used, but I have no idea how many hours are on it.

At this point, the Sony is definitely more revealing of nuances and details in the recordings than the Rega. The Sony does great imaging/soundstaging and has lots of air/space between instruments. I'm definitely hearing more attack on the front end of instruments, as well as subtleties I didn't notice before (e.g., tremolo effects on guitars, doubling of vocals, low-mixed instrumental lines etc.). The 5400 does a great job of sorting out complexities in the mix. The bottom end is also both clear and full.

The Rega Saturn may be a tad warmer sounding, overall, with a bit more "meat on the bones." It has a more organic flavor and a bit less of a "hi-fi" presentation than the Sony 5400. If you like hearing the venue and the fine details, you may prefer the Sony (although you're going to hear "warts" and problems in the recordings, too).

Honestly, it may be easier to forget you're listening to digital on the Rega. It does all of the hi-fi stuff, but with a slightly less analytical approach. Both players are great sounding, but with quite different presentations. For now, I'm really enjoying the Sony 5400.

Note: I've been a drummer for a very long time, so my hearing in the upper mids/lower treble is definitely not what it used to be. Needless to say (I'll say it anyway), my subjective preferences, my room, my gear, and (especially) my ears are not yours. As such, your experiences may vary considerably. That said, I would not hesitate to recommend that you give the Sony a listen in your own rig. I've been enjoying the heck out of mine. Good luck!

Do you think a week is long enough to tell what it sounds like? I hear the Sony needs a long break time.