LND150 loop

[Vlada]

Hello guys, I am trying to create pcb layout and build fx loop from the schematic I have found on Effects loop topic here.
Can someone help me to understand what is the purpose of 3k3 resistor in series with 470r?
1k5 in series with 1M resistor also looks strange to me, is that a mistake on the schematic?
Thanks in advance

[2deaf]

Hello guys, I am trying to create pcb layout and build fx loop from the schematic I have found on Effects loop topic here.
Can someone help me to understand what is the purpose of 3k3 resistor in series with 470r?
1k5 in series with 1M resistor also looks strange to me, is that a mistake on the schematic?
Thanks in advance

The LND150 is radically non-linear, so it would be beneficial to have some source-to-gate negative feedback to make it more linear.  But increasing the source resistor gives an undesirable bias point, so the 3.3K resistor is added to provide some negative feedback.  A negative feedback loop from the drain to the gate would require very large resistances in order to have a high input impedance for the LND150, so it's really not feasible.

The 1.5K resistor in series with the 1M resistor isn't a mistake on the schematic.  The mistake is with the PCB which is configured exactly as the schematic shows.  The 1.5K resistor should go between the 330nF capacitor and the LND150 gate with the 1M resistor connected to the junction of the 330nF cap and the 1.5K resistor.