tried ZX-300, the black brick and the gold brick with Sony top of the line Z1R at Sony Store Singapore, can't really comment on the sound cause the stupid shop is blasting Christmas songs near the testing counter, bodolol

but if you have a hard to drive headphone, ZX-300 is a no, I have to push the volume up to 80% at normal gain to have a decent listening volume, and which high gain, I can hear the sound start cracking.

But for me the difference between black brick (1A) and gold brick (1Z) are no significant, if I have the money to spend I will go for 1A, if...

But with that price range I can go for AK already...