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.The gain of the latest model of AIYIMA A07 is much lower than that of the previous model, probably because the circuit has been changed. Therefore, the measurement data of amirm may not be applicable to the latest model.