Based on the #18, JC-3 use the invert input as the input. Be aware that the impedance of the source would change the close loop gain and the stability. Other than that, the amp is pretty much perfect to my opinion.
I played with that circuit, long long time ago.
I also played with all those sorts of JFET input stages, from simple single to JFET quad.
https://pmacura.cz/diyaudio/jfetdist.htm
I also played with all those sorts of JFET input stages, from simple single to JFET quad.
https://pmacura.cz/diyaudio/jfetdist.htm
