MXL 770 Mods
Headbasket Mod, Microphone-Parts.com Mod w/ RK-12 Capsules, and Cardioid / Omni Switch Mod
The MXL 770 LDC mic is yet another decent mic as is, but it can be improved fairly easily with several mods. Actually, though MXL refers to this as a LDC, in reality, like the MXL 990, it uses the same SDC capsule as the 991 and 603 pencil mics, but with a brass ring around it that makes it look larger when viewed through the fairly dense grill.
The first mod involves replacing a lot of the parts on the circuit board, including the cheap capacitors in the signal path, the JFET and Transisters, and some of the resistors, using this kit from microphone-parts.com. This particular kit included all of the parts required for the signal path electronics path mods, but uses the original circuit board, and retains the pad and high-pass filter switches. They also have a nice looking kit that replaces all of the parts, including the circuit board. We haven't tried one of these yet, but in some ways, it is probably easier to build, as you don't need to carefully remove parts from the original board, which can be be a bit tricky to do without damaging it.
For this pair of 770s, we also replaced the SDC capsules with matched pair of Microphone-Parts RK-12 capsules from microphone-parts.com as well (the kit price includes your choice of one of their capsules). These are based on the old AKG C-12 style capsule, and are side terminated, rather than center terminated.
The second mod involves opening up the head grill, and the third involves adding a small switch at the base of the body to switch the RK-12 to either Cardioid or Omni modes. This switch is mounted inside the body, near the base, and is accessable by unscrewing the base of the body - the body itself does not need to be removed.
The headbasket mod process is identical to the process for the MXL 990, and is illistrated here.
So, on to the MXL 770 Microphone-Parts mod...