Hello Im tring to analyze a circuit and it has this switching circuit that I dont really understand (especially the diodes part ).
Can anyone help me ? Thanks !

 

What is the nature of the signal?

 

electric guitar

 

Do you have better quality (large) schematic?

 

attached

 

It seems that the JFET is ON when the gate is left floating via D1 (D1 prevents the JFET gate to channel diode to conduct) and a positive voltage at the FS2 point. And when FS2 is at ground the JFES is OFF.
I suspect that the 10μF capacitor was add to slow down Turn ON and Turn-OFF time used to prevent "pop sound" when switching between ON/OFF.
And it is a mystery to me why they add into the circuit the D2+100k resistor in parallel with the 1k resistor.