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.