Picked one up at a very low price to use it with a USB dongle. Quickly measured its 1 kHz sine tone SINAD:
View attachment 437082
This is equivalent to Amir's AP result (SINAD 118 dB) considering mine must have added slight harmonic products from my DAC/ADC setup (E1DA 9039S / Cosmos ADCiso).
However, as some members observed in this thread, this amp seems to be very susceptible to AC and RF noise. Across my multiple measurement trials, I noticed some variability of its noise floor. For example, as Amir mentioned in his
Sabaj A10h review, this amp's noise floor also increases quite a bit when its output ground is made "floating." See below:
View attachment 437088
As a result, SINAD worsened by 10 dB. Of course, amps and DACs can suffer from AC/RF noise when their ground is not connected to test gear. But the adverse effect is not to this extent. Wolf at L7audio also observed the same phenomenon in his
A10H review.
But then why? Two potential causes: (1) quality of the included power supply; or (2) the circuit GND is not grounded to the case.
I will look into both. Any suggestion?