I do not work for the company, just own one of the Z4,
@amirm Is there a direct email for Dan to chat with you? I did get some more information from him. It looks like his off-the-shelf samples differ from as-built house specs:
I followed the link, but still couldn't find contact info for Amir...I'm probably being a little blind.
The funniest thing about the review...Amir seems bothered by the flat THD characteristic. He praises its low noise...that's why the THD limit is so flat-ish...the NAD he shows is dominated by noise, that's why its THD is so high at low levels.
GT-108 has very low noise, so its THD doesn't rise at low levels.
His main complaint..
1. He wants more power for the bucks...OK
2. He wants better multi-tone results...OK
Point by point:
ASR 5 Watt measurements were -72 2nd harmonic. My off-the-shelf sample was -83...Not sure why the difference, but it would move us up significantly, making us better than anyone on the zoomed-in chart. What was the source of this unit?
The noise was better than most.
Frequency response was wide and flat, with "of course no load dependency"
Multi-tone was 13.3 bits (fair)
Two-tone Distortion-free range =13 bits (fair)
Channel separation at 75 dB at 1 kHz (fair) Note that this is so high at 75 dB that it could have no bad effect on anything.
Flat distortion--Why? Cause our noise is so low!!!! 0.012% versus 0.003% is probably an old carryover/typo. We agree with the 0.01% characterization.
The amplifier has an "amazing amount of headroom".
Power and pop level is quite acceptable 200 mV worst case, audible, but no concern
It's a very good review...the only thing ASR complains about is low power output for the money. Compared to many amps, this is however a very good value.