In case anyone wants to know you can swap out the Internal Mic Cartridge for a Motorola 5080258E18 Internal Electret Microphone Cartridge. On the MXT400...Don't forget the drill the mic hole 1/16 of a inch...and put cotton balls in to tighten the sound. I got great feedback on my sound quality. Tip:unsolder from the board. I try d to upload the pictures but it says file too big.