Nice review! From the measurement, 70 dB SNR at output 108 mV, which will be around 73 dB with A weighting, usually hiss noise will be easily heard on IEM. So, I'm curious that in your test you didn't any noticeable hiss with IEMs. Anyway, it does look like a very interesting amp indeed!

Would be nice to see comparison with ALO V5,CDM or WA8 Eclipse

@earfonia thanks. In Sassy II case, the lower (70dB) SNR is mainly caused by the higher 2nd harmonics even though the amp inherent noise (hiss) is around -120dB. Maybe my IEMs or ears just aren't sensitive enough to notice it. Cheers.

@crabdog Ok, that makes sense! Thanks!

Wonderful Review!  Great work!

@BloodyPenguin thanks very much.

Enjoyed the review, sounds like a great little amp.

@Sonic Defender thanks. It is an amazing little amp. Highly recommend you audition it if you get a chance.