Electret Wiring: Is it strange?

[Mike Watterson]

Actually thinking about it a bit more, because the JFET has high AC output impedance, see slope of Id vs Vds, the battery noise is not halved by resistor & JFET divider in fig 1.

  2SK1109.pdf (Size: 47.46 KB / Downloads: 1)
(PDF download of 2SK1109, typical of JFET used in ECM)

In reality fig1 and fig2 will be more similar battery noise, which in practice might be 100 times lower than any PSU or laptop mic in.