Multitrack Microphone Circuit Kit

This kit creates a neutrally-voiced, large-diaphragm condenser microphone that allows you to choose the polar pattern at mix time. It has separate outputs for the front and rear halves of the capsule; by recording both to independent tracks, you can control the effective polar pattern after tracking is complete. (See the mix matrix below.)

The circuit is our acclaimed transformerless design, implemented with high-grade parts. The circuit incorporates a next-generation corrective EQ option.

The finished mic has high output (~35mV/Pa), low noise, low distortion, and a very smooth (not bright or harsh) response. It is suitable for voices, acoustic instruments, foley, and ensemble miking.

We offered a version of this kit in April 2020. We have revised, updated, and upgraded the product; the new version was introduced in June, 2023.

In The Box

This kit contains:

• two circuit kits for DIY assembly
  
• a 5-pin XLR insert to be retrofitted into the donor mic
• a selected RK-87 capsule (value $159)
• an XLR5 breakout cable (XLR5F to two XLR3M), built in-house using Neutrik connectors and Gotham GAC-3 cable (value $119)
• a detailed build/installation guide

The donor mic is not included in this circuit kit.

Compatibility / Requirements

These PCBs fit the MXL 920 and MXL 890. This kit is not known to fit any other microphone. (We suspect it will fit the CR89, and might possibly also fit the Revelation Mini, but we have not confirmed compatibility.)

If your donor mic is anything other than. the MXL 920 and MXL 890, you can determine compatibility by printing this PDF template of the Multitrack PCB at 100% scale; cut out the template and compare to your mic's chassis. If the chassis can accommodate two of these boards, and the mounting holes match, then your donor mic is likely compatible with this circuit kit.

Optional Upgrades

The modified MXL 920 is compatible with the Rycote USM-VB, which we use and recommend.

Skill Level

This kit is comparable in difficulty to the MP-V57 or any of our other transformerless circuit kits (although, technically, this kit contains two of them).

We do not recommend this kit for people who have never soldered before, nor for first-time mic builders -- see the S-25 kit instead.

The Non-DIY option

If you own a compatible donor mic (see list above), we can transform it into a multitrack microphone. Contact us for details.

Mix Matrix

After recording with this mic, combine the two recorded tracks as follows to produce the indicated polar pattern: