MXL 990 Mods
Headbasket Mod, Capacitor Mod, and RK-47 Capsule Mod
The MXL 990 LDC mic is 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, 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 all of the cheap capacitors in the signal path with higher quality caps. The second involves opening up the head grill, and the third involves replacing the K-67 style capsule with a higher quality true LDC capsule. As mentioned in the other mic mod sections, the K-67 style capsule has a peak in the response curve up around 8k, which gives it a somewhat brittle sound. The original Nueman U-67 mic had some EQ circuitry to smooth this peak out, which had the effect of noise reduction in the upper frequences, while the MXL 67G (and many other Chinese clone mics) do not have this EQ circuitry, so they can sound a bit bright and brittle.
For the capacitor mod, we bought a selection of Wima caps from Mouser, the grill mod only requires a few hand tools, and for the capsules, we used a matched pair of K-47 style capsules from microphone-parts.com (we modded a pair of 990s). We have also used some of their K-12 and K-7 style capsules, as well as one of their MXL 990 mod kits that replaces most of the caps, plus the FET and a few other parts, and we are very happy with them. We would definitely recommend them for mod parts, especially for the capsules.
Ok, first the headbasket mod...