Rebuilding Your Microphone

I rebuild many different mic models from MXL, Sterling, CAD and others. The entire guts of the microphone are replaced with premium components. Contact me for more information.

Why Rebuild?

Entry level mics from MXL and others are fine for getting started, but they are generally poor performers. To hit the price point, they are often using Small Diaphragm Condenser (SDC) Capsules (even though they look like LDCs). The circuits are mass produced with low cost surface mount components. The result is often a thin, dull tone with an over-hyped top end.

The Capsule

Capsule, Saddle and Board

I replace the capsule with a high quality k47 style LDC capsule. This capsule yields a much flatter response than the typical stock capsule. It offers fill lows, rich harmonics in the mids and a smooth un-hyped top end.

The capsule is mounted in a nylon mount which I have custom fabricated in the USA.

The Circuits

My transformerless all-discrete jaSb circuit fits in standard tall cylindrical mics from MXL such as the 910, 440, 550, V250. It will also fit in any “BM800” style mic – even the cheap-o ones from Amazon! A specialized version of the board that fits in the MXL 990 and MXL 920. I use high quality components including low noise resistors and WIMA film capacitors in the audio path. Based on the Schoeps CM5 circuit, my jaSb (just another Schoeps board) is my take on this common elegant design.

My transformer-coupled BFM board will fit in most transformer coupled mics from MXL and others such as the MXL 2001. With a small adapter board, I can also transformerize most mics! A special version of the BFM designed for the Sterling Audio ST55 (or Groove Tubes GT55) supports the Pad and Filter switches (and gives you an internal pattern switch). The BFM is based on the Neumann KM84 circuit but adapted for LDC capsules. It has an extremely minimal audio path. The very few components in the audio path are high quality including low noise resistors and high quality film capacitors. I use 7:1 imported transformer (China) but can optionally use a Tab Funkenwerk transformer from AMI (USA). You can read more about that here.

Both circuits have an optional internal pattern switch for selecting between Cardioid and Omni patterns. Without the switch, the mic is fixed as Cardioid.


MXL 990

The 990 version of the jaSb board is for the MXL 990. This board also fits in an MXL 920 which is fantastic mic to mod (albeit a bit rare).

Like the standard board, there is an optional internal pattern switch to select Cardioid or Omni. Without the switch, the mic is fixed as Cardioid.


Common Tall Cylindrical Mics

This is basically the everything else category. The standard versions of my jaSb transformerless or BFM transformer-coupled boards will fit in most mics from MXL, CAD and others.

Transformerless Models in this group are: MXL 2006, MXL 2008, MXL 910, MXL 909, MXL 870, MXL 550, MXL 440, MXL V250, MXL V63M, Tascam LD-74, MCA SP-1, Nady SCM-800, CAD Audio GXL2200, CAD Audio GXL2400, Scarlett Studio, Other “BM800” Amazon cheap-o mics.

These mics can be rebuilt as transformerless with the jaSb board or in many cases can be transformer converted with my BFM board and an adapter board.


Sterling ST55

The ST55 (or Grove Tube GT55) is a fantastic mic to rebuild. The mic features a heavy solid construction and switches for Pad and Hi Pass (low cut) filter. My BFM-T-55 board is designed for these mics and has an internal pattern switch. I replace the standard Sterling “Resonator Disk” capsule with my standard k47 style capsule. The hp filter swtich kicks in at about 135Hz.


How To Get Rebuilt

Contact Me about your microphone

Choose and purchase the rebuild option

Ship your mic to me and provide tracking number

I will rebuild, test, burn-in your mic

I will return your vastly improved mic to you.

I typically turn around mics pretty quickly. After the rebuild, I let them burn in for a full day and do multiple listening and technical tests on them.