The A07/A04 I own is the earliest model and I haven't bought the latest one yet.That's interesting. I've started using the 32v power supply with the A04, it was almost too loud with the A07 I have. How is Aiyima indicating their model revisions, Toku? Is it on the main circuit board? I've been planning to try the A07 with my one 24v supply from SMSL where the plug fits their socket, but hadn't gotten around to that yet.
Some people who purchased additional A07 at the Japanese forum reported some complaints that the latest model had lower gain.