Hi,
I agree with the initial post on this thread...the ZX507 is beyond the AK Cube. In so far as my own experience; I've owned several DAP's including the AK240, AK Cube, Sony WM1A... this one somehow trumps all.
I'm using iem's for the most part and most recently purchase CA Andromeda's (V3, 2019 model)... the sound quality and layering has me hearing detail and nuances in hi-res files I simply didn't before... of course this has a lot to do with both your head/earphones as well as the SQ of your files. That being said the soundstage is significantly better than any other source I've heard as well.
I disabled most items in Android as well, and can attest to the only real issue being the touted battery life isn't as advertised, but frankly, that applies to all DAPs...
I also use USB Audio Pro and direct sound processing vs. Android processing... it allows the best sound quality vs. the Sony App (which is already fantastic) and allows direct access to TIDAL without using the TIDAL app... it works great and sounds easily as good as the proprietary app.
I bought mine from a seller on eBay from Japan, with the case... ended up being the same price as it will be in Canada - once they are actually available.
Last point - I had to run my various head/earphones at "80" on other DAPS to really hear all elements of any track... on the ZX507 and the Andromeda's I'm usually at 40-50 (out of 120 steps available)... the sound is that clear and articulated - plus these iem's run at 12 OHMs so less power is required...
No need to drive into the observations or verbiage of blacks, mids, transparency, clarity, bass... all this player requires is a listen of a hi-res file with a decent pair of iem's or headphones...you will be sold.
+ Quick add - sorry, I should have noted that best results are always with a balanced connection; currently using a Sony Kimber Balanced cable, have a iBasso's MMCX balanced cable as well but the Sony seems to sound better with Acoustune 1551Cu iem's, Shure 846's, and with the CA Andromeda's...
Dave