Circuit Upgrade Kit for MXL 990

This is the original drop-in upgrade circuit kit for the MXL 990. Beware the lesser products from copycats. The version sold here was developed as a full implementation of the Schoeps CMC5 circuit, using high-quality, hand-picked parts. Revised & Upgraded in 2021 We've done extensive revisions to this product over the years, most recently in April 2021. The latest revision provides improved noise filtering at several critical points in the circuit, and a more stable DC oscillator.  Included with kit New, custom designed, 2-layer circuit board; lead-free ENIG finish 100% of PCB components necessary to build the microphone, including matched capacitors and a pre-biased JFET to maximize headroom while minimizing distortion Additional capacitors to allow you to tune the high-frequency response of the circuit to accommodate brighter-voiced capsules such as our RK-87 and RK-12. Full-color, step-by-step instruction booklet Internal switch: configure it for either pattern (Cardioid/Omni)