Just got my SR25 and here are a few first impressions — I'll be posting a review on Empeiros Audio in the coming days (weeks?).
Usual disclaimer: I have a preference for an open, lush/smooth/warm sound with some definition, texture and soundstage — none to excess. I am not into an analytical or clinical sound.
My past DAPs were, in this order: Cowon Plenue D, Cowon Plenue M2, Sony ZX300, HiBy R6 Pro, HiBy R5, Astell & Kern A&norma SR15, Astell & Kern A&ultima SP1000M.
My all time favourite always has been the Sony ZX300 which was dethroned by A&K's SR15 who's sound I preferred although it ended up sold as I found it too small.
The last DAP I owned was A&K's SP1000M so my comparison, from memory, will mainly be with this latest DAP, paired with Campfire Andromeda Special Edition: Gold (with their stock, SE, cable) which I'll finally keep.
Overall, I prefer the sound signature of the SR25 over the SP1000M, without hesitation.
I know this next comment might generate a stir but the SR25 is also as fast, if not faster, than the SP1000M — no question about it (the new Android base of the SR25 might be the reason).
The screen resolution and size are just about perfect for a genuinely portable DAP. Although the SR25 still is small-ish, it isn't as annoying/restrictive as the SR15.
It's overall build and design makes it the first DAP, together with the ZX300, which I want to use
without a case just to the feel the DAP for what it is: an exquisites piece of design and hardware.
A&K finally included matt screen protectors for the front and rear which are of good manufacture compared to the ones bundled with the SP1000M which were a disgrace.
EDIT: I also find the SR25 volume wheel to be better implemented than on the SP1000M.
EDIT 2: It's also nice not to have to handle a DAP like it is nitro-glycerine (with the SP1000M worth 2k… I kinda struggled with that)
EDIT 3: Quick picture — testing the SR25, balanced, with WiFi on
