Microphone research

Robin Whittle rw@firstpr.com.au   September 2009

These pages contain photos and other information for people with a technical interest in how microphones work.

2009-09-a  Photos of some Transound electret microphone capsules I recently purchased from JLI electronics.  This includes dismantling a TSB-120A, a TSB-140A, a TSB-140AO and a TSB-2555A.  This page also includes links to the Micbuilders mailing list.

2009-09-b Researching what may be a novel way of pre-amplifying electret microphones which provide independent access to the source and drain of the inbuilt FET.  This may also be useful for constructing pre-amps for elecret or externally polarized condenser microphones which have no FET.  It offers freedom from the "DC Thump" problem which seems to be the limiting factor for high SPL usage of the traditional Grounded Source and Source Follower modes of operating electret capsules which have internal FETs.  On the cartridge I tested, it also achieves much lower distortion at 140 dB SPL, which is 20 dB above the specified maximum SPL for this cartridge.  Still, there may be limitations of the capsule other than actual distortion which limit how high an SPL it can operate with.