Dachman Audio K47 Series 2 - Upgrade/Replacement for RK-47 K47 Mic Capsule | eBay
Custom U47 mic test (RK47 capsule and MP-V57 PCB kit) with Chesqua. - YouTube
Mic-Parts mods for MXL 990 condensor microphone - DIY: Build it and they will come Forum - KVR Audio
Microphone Parts: RK-47 mic capsule, RK-12 mic capsule, 990B PCB Kit | Tape Op Magazine | Longform candid interviews with music producers and audio engineers covering mixing, mastering, recording and music production.