MXL 870 Mods

We offer two modification/upgrade options for the MXL 870: replace the capsule with one of our premium large-diaphragm models, and/or upgrade the audio circuit with the amazing MP-V57 circuit.

#1: Capsule Replacement

The small-diaphragm MXL 870 capsule tends to have an uneven, peaky response. The mic sounds much more full, warm, and balanced after a true large-diaphragm capsule is installed.

If you choose to leave the circuit as-is, install an RK-47 capsule. It will give your mic a neutral top end, great midrange detail, and a much more balanced sound.

Alternatively, the RK-12 capsule would give the mic a very open top end, balanced by a full bottom end. This capsule works with the stock MXL circuit (although it must be said that most of the MXL circuits we have measured tend to be higher in noise and distortion than is ideal for studio recording). Both the RK-47 and RK-12 can be used with the stock circuit, but both sound better with our MP-V57 circuit; see below.

The third capsule option is the RK-87. Because this K67 style capsule has a rising frequency response, we recommend using it only with our MP-V57 circuit, because our circuit provides optional high-frequency attenuation -- which gives the RK-87 capsule an essentially flat frequency response.

#2: MP-V57 Circuit Replacement Kit

The MXL 910 is a wonderful container for our top-of-the-line transformerless PCB kit, the MP-V57. This is a full circuit replacement, using uncompromising audiophile parts.

Click for more info on the MP-V57 PCB kit.