Thanks Richard, valuable stuff!
A word of caution about noise simulations: assuming many of us will be using LTspice, then first check the JFET models you use. Many of the JFETs in the standard.jft library have unrealistic or just plain wrong flicker-noise Kf values. They are either equal to the default value (0) or they can be off by a factor of 1 million, like many of the Linear Systems JFETs.
Got my SC140 working again. It turned out the XLR screw was overturned and the pressure of the screw head to the mic body had become too low to establish a low rsistance contact. I replaced the XLR with one from Aliexpress with a scraping ground tab. See one of my earlier posts for the link. I measured the sensitivity and measured 15.2mV @ 94dB SPL, which is quite close to the 16.2mV as advertised by t.bone. I use a Umik-1 mic as reference and REW for the measurements. Will try to do noise measurements later, both on electronics alone and (for what it's worth) on a complete mic.
Jan
