I completed my build: I rebuilt the amp boards with new PCB with improved layout and went back to the original Naim regulator circuit for the power stage. The amp sounds very good and behaves better, see attached scope shots:
20kHz square wave (0.5V input) into 8R and 1uF
20kHz square wave (clipping with 3.5V input) into 8R and 1uF
20kHz square wave (0.5V input) into 8R and 1uF
20kHz square wave (clipping with 3.5V input) into 8R and 1uF
. We don't often see any objective measurements of Naim or related high-end circuits in discussion here.Hello jpk73!
i see your new amp is very very stable on square wave it's impressive.
when I improved the stability of my old amplifier on its regulation and amplification board I also found an audible improvement especially with the improvement of the power supply board in fact.
As for objective measurements, I now have new very low distortion loudspeakers and I have done some ABX tests (so on the whole chain and not just the amplifier)
I passed the test at 0.1% distortion at 19/20 which means that the whole hi-fi system is below, a NAP250 being at 0.03% I think my version must be close to that even if I don't have a distortion meter.
https://www.audiocheck.net/blindtests_index.php
i see your new amp is very very stable on square wave it's impressive.
when I improved the stability of my old amplifier on its regulation and amplification board I also found an audible improvement especially with the improvement of the power supply board in fact.
As for objective measurements, I now have new very low distortion loudspeakers and I have done some ABX tests (so on the whole chain and not just the amplifier)
I passed the test at 0.1% distortion at 19/20 which means that the whole hi-fi system is below, a NAP250 being at 0.03% I think my version must be close to that even if I don't have a distortion meter.
https://www.audiocheck.net/blindtests_index.php