If someone would like lower gain the feedback resistor R22 could be lowered to 100 Ohms for about 6dB less gain.
This of course changes the feedback and maybe the sound but it will be stable.
The two box solution is the best from a noise standpoint of course. I am running one box with an Amgis 25 VA toroid and a Zu Denon103 and it is fine.
With a Vandenhul modded Ortofon MC2000 I do have some noise ear to the speaker and would prefer the two boxes.
The J112 bias isn't super critical as long as you can bias up the output transistors, 2-8 mA is fine and the LEDs will last years. This current changes the distortion via lowering the second harmonic about 5-6 dB. It is a bit hard to see among the total Thd+n but you can see it. My simulation shows it pretty well without the noise.
This of course changes the feedback and maybe the sound but it will be stable.
The two box solution is the best from a noise standpoint of course. I am running one box with an Amgis 25 VA toroid and a Zu Denon103 and it is fine.
With a Vandenhul modded Ortofon MC2000 I do have some noise ear to the speaker and would prefer the two boxes.
The J112 bias isn't super critical as long as you can bias up the output transistors, 2-8 mA is fine and the LEDs will last years. This current changes the distortion via lowering the second harmonic about 5-6 dB. It is a bit hard to see among the total Thd+n but you can see it. My simulation shows it pretty well without the noise.