LDC Mics

We rebuild and mod a variety of LDCs from MXL, Sterling, m-Audio and others. The donor body can come from you (mod) or from our stock (pre-mod). Either way, we offer a choice of Transformerless (TL) or Tranformer-Coupled (TC) mods to many low cost and under-performing mics. Our circuits are hand-assembled with high quality low noise components and point-to-point Capsule to FET wiring. All prices and options are explained below. Feel free to contact me with any questions. Or you can go straight to the Store and see all of the offerings.

LDC Capsule Flavors

mic mod capsules

Our standard configuration is to use a K47-style Center-Terminated LDC Capsule. The k47 design yields a wide, flat frequency response with full low-end, harmonically rich mids and a smooth, non-harsh top end. The K47 paired with our Transformerless jaSb circuit, is extremely versatile. That is the configuration used in every mic on the Mictastrophe video.

Optionally, we can use a CK12-style Edge-Terminated capsule. The CK12s have a little less of that mid-forward energy of the K47 but more of an extended silky top end. They are generally brighter sounding and they pair nicely with our Transformer Coupled circuits. They will put a nice top end sheen on background vocals, or stringed acoustic instruments or percussion.

Transformer Choices

  • 3U Audio GZT-84 7:1. The 3U is a slightly lower cost transformer that has a tiny bit less low end than the other options (we’re talking -0.5dB at 50Hz). It has plenty of transformer mojo with low frequency harmonic distortion and sounds wonderful on vocals, acoustic instruments. Overall, it will sound just a bit brighter than the other options)
  • CineMag 5722w 6.9:1. This is a very high quality transformer yet still moderately priced. It is CineMag’s recreation of the BV107 that was in the KM84 which our circuit is based on. Overall, this is probably the one to go with for most applications.
  • AMI Tab-Funkenwerk 6.5:1 T12 style. This is the highest price option and is very high quality. It has very full lows and low-mids with lots of great harmonic distortion. It is the definition of fat! It’s an excellent choice for low frequency applications like Kick Drum or Bass Cabs. It’s not dull by any means, but because it is so fat and full in the lows, it can make the overall tone of the mic heavy and slightly less bright. The AMI is also a great choice for CK12 capsule build because the brighter capsule compliments this full bottom end beautifully

LDC Circuit Flavors

All of our circuits use a directly coupled FET at the capsule input. But we offer two distinct flavors of circuitry: Tranformerless and Transformer-Coupled. What’s the difference?

Transformerless (TL)

Our all-discrete jaSb (just another Schoeps board) board is a “Schoeps Style” circuit built with high quality, low noise components. This circuit is based on the Schoeps CM-5 which is a elegant microphone amplifier circuit and is the basis for most Transformerless (TL) mics built today. The slightly self-deprecating “just another” in the acronym is because this is a very common approach for TL mics. Our board uses low noise Vishay/Dale resistors and WIMA capacitors in the audio path. It also has an improved voltage regulator which lets these mics work perfectly on low phantom power voltages (like some Behringer products or video equipment will provide).

Transformer-Coupled (TC)

Our BFM Transformer coupled circuit is based on the Neumann KM84 mic circuit adapted to an LDC. This elegant design yields an incredibly pristine tone with some transformer mojo and very low noise. Neumann’s KM prefix stood for Klein Mikrofone – small microphone – like the KM84 and KM184, etc. Being adapted to a large capsule, we gave our circuit the BFM (Big F’n Microphone) prefix.

The BFM is made in multiple footprints to fit many different mics – including MXL 990s.

We have BFM versions for the Sterling Audio ST55 and MXL 992 which support the Pad and HP Filter switches on those mics. The BFM boards support an optional internal pattern switch. The BFM can be used to rebuild an existing Transformer-Coupled mic (such as MXL2001) or we can transformerize a TL mic!

MXL 990

The 990 is a very common much-maligned mic that makes an excellent donor body. We can rebuild it as a TL or transformerize it to become a wonderful Transformer-Coupled mic.

See the LDC Flavor Guide here.

Sterling Audio ST55

The ST55 is a Transformer-Coupled mic with pad and filter switches. Our BFM-55 board is designed specifically for this mic to support the switches. Only the K47-style capsule can be used in these mics.

Other Donor Bodies

This is the everything else category. Most of the tall cylindrical shaped mics from MXL (like the 910, 550, v250, v63m etc.) fall into this category. We have both jaSb (TL) and BFM (TC) boards that will fit most of these mics. This even applies to the $20 Amazon BM800 style mics!

Odds and Ends

For some mics, it makes sense to do a capsule-only mod. Or you may have acquired a great capsule and want our electronics only. We can do that…