Quad fet switches

[dbanner]

I was having a look at some old schematics and came upon this White's 6000D schematic from the service manual.
4 fets are arranged for switching the phase shifters instead of the usual 2.

Interesting schematic.

[waltr]

I was having a look at some old schematics and came upon this White's 6000D schematic from the service manual.
4 fets are arranged for switching the phase shifters instead of the usual 2.

Interesting schematic.

Yes, interesting.

Looks like one JFET is ON when the other is OFF from the Gate scope diagrams.
So when NOT sampling the signal is Grounded.

[dbanner]

Yes, pulling the preamp output to ground may avoid gate charge injection issues with the substantive switching fet.
2N4302 is run of the mill N-JFET.