Firstly, when I got my ZSA's, I got a free cable as well, it is also the wrong type, it fits the ZS10 better but not the ZS6 or ZSA!
Tonight I have had a chance to do some comparisons between my ZSA, ZS6 and ZS10 headphones, one thing I did find is that all of these headphones can be tuned to suit by using the right tips. And another point I found was that the ZS6 does not like the standard cable, it makes them sound sibilant and changing to the KZ silver cable makes such a difference.
I began by using the ZS10, I considered it to be a good all round headphone, the soundstage is right around you and you are in the middle connected with the music. Everything sounds like it is in the right place and the sound is just right! Bass is enough and well controlled, not over blown.
While the first time I tried the ZSA, (only really run for about 4 hours, so not really a fair comparison.) I found it to have a much darker sound and heavily bass dominated which was making the vocals slightly recessed and not very clear. Soundstage was good but away from the listener, almost funnel like in the sensation and very slightly sibilant.
Changing to the ZS6, bass was good, well controlled, still more than the ZS10, soundstage was immersive and widespread but vocals were very sibilant, annoyingly so! The midrange is forward but the very upper midrange was recessed. And the sibilance was causing cymbols to be tizzy instead of having a zingy sound.
Once I started changing tips, the ZSA eventually became fun to listen to but very mid, mid forward, and as it ran for a while and got warmed up, the bass began to go back into a place of sensibility and control, much reduced from before, which began to relieve the midrange to start coming forward and more balanced. After and hour and a half, it had all settled down but the ZSA is still very mid forward compared to both the other headphones and when I changed back from the silver cable to the brown one, sibilance came back with a vengence on the ZSA also.
Back to the ZS6, a change of cable to the KZ silver and the sibilance just disappeared completely, everything became so much clearer and with the right tips, again a well balanced sound was produced. In fact, I began to fall in love again with these headphones, that much of a change!
Another thing of notice, the ZSA needs quite a bit more power to run at the same volume as the other two but it doesn't lose it's detail at lower volume thankfully. As always, this is my opinion, you form your own, this is just for me to give my personal opinion! And to be fair on the ZSA, it has only had a short run time, the fact that it changes so much over a short listening period means to me that it has not yet been fully run in and needs more time to settle.