CM1800 Microphone Mod Kit

We recently discovered a new, super-low-cost donor mic option: the Stellar Labs CM1800 -- as of this writing, $32 via Newark. The CM1800 appears to be identical to the Tascam TM-80. Therefore, this upgrade kit is believed to be compatible with the Tascam TM-80 as well as the Stellar Labs CM-1800. We can't recommend the mic  for recording in its stock form, but it makes a decent "donor mic body" thanks to its robust construction. About the Mod Kit This DIY kit replaces the mic's entire signal path. The new capsule is larger and sounds better. The new circuit has higher sensitivity and lower noise. The modified mic provides better bass response, a more open top end, better upper midrange detail. We use premium passive components that are widely recognized for their sound quality: Vishay-Dale resistors, Panasonic electrolytics, Wima polypropylene film capacitors, NOS transistors, etc. The circuit board is a premium 2-layer design. We individually select the JFET for low noise, and "bias"