These are the circuit boards I've designed over the last few months to use for upgrading cheap fake "studio condenser"  microphones or building good quality microphones from scratch, if used with suitable casings etc.

They are designed so they can be assembled in various different ways with different groups of components fitted for different applications and numerous different circuit arrangements, with either two terminal electret capsule, three terminal electret capsule, "bare" electret [untested] or a true condenser capsule, in combination with a second PCB to supply the capsule bias voltage.

These are the final PCBs; the audio board, and the optional bias voltage generator that works with it for true condenser capsule use. They are double sided plated-through boards with topside ground plane and solder resist on both sides. There are more photos in the "parts lists and schematics" files just below.



The PCBs are available for purchase via ebay, through the link below - £6.99 for a single PCB or £10.99 for a pair of boards, with free postage in the UK.

ebay listing for these PCBs


The parts lists and schematics for each board are here:

Mic audio PCB parts and diagrams

Mic bias power PCB parts and diagrams


More information about the various mods and tests is included in the Microphones playlist on my YouTube channel, here:

Robert Jenkins Technology channel - Microphones playlist 


Modification results, using a cheap NW700 as the donor casing, a £12 condenser capsule and £1 K118 JFET, all from ebay; front view:


Rear view:


And the noise level test results in a direct comparison against an MXL V87, with gains equalised for wanted audio - Green V87, Magenta my mic, grey is both overlapped.



For comparison, two different age versions of unmodified NW700 mics vs. the V87: