Comments on: Microphone Impedance: What Is It And Why Is It Important? https://mynewmicrophone.com/microphone-impedance/ Dedicated to teaching you music production and all things audio! Mon, 03 Feb 2025 17:42:03 +0000 hourly 1 https://wordpress.org/?v=6.8.5 By: Marc Draco https://mynewmicrophone.com/microphone-impedance/#comment-12254 Sat, 23 Mar 2024 20:02:27 +0000 https://mynewmicrophone.com/?p=24#comment-12254 I’m confused where they get 50 ohms (or less) for output impedance when the mic needs (at the very minimum) a JFET impedance convertor and it’s unlikely you’ll get much change out of (my mate used 2K2 in source and drain circuits to get an approximate phase/antiphase response at 30V) but that’s a world away from the sort of negative feedback needed to tame the non-linearity in the FET and that means more transistors.

Negative feedback can reduce the output impedance down to a fraction of an ohm in very high-gain amplifiers but they take a lot more power to run, IC/ASIC ones in particular, although ASIC is preferred.

But I see lots of designs based around the classic Schoeps circuit that put 47R (typically) in the emitter circuit loaded by the 6K8 resistors in the P48 supply which taps out at just 15-mA (more realistically around 10-mA where there’s still something left to power the active components.

]]>