I am always a sucker for cool, older microphones that critics say still have great mojo. I was interested in enhancing my inventory of acoustic instrument microphones (guitar, piano, drums, winds), and read some articles about the 1970s-90s era AKG C451E. I found a pair for a good price, and just got them today. These small diaphragm condensers are modular - the preamp body is interchangeable with various capsules. I scored a C451E with a CK-1 capsule, and a C451EB with a CK-5 capsule (I can unscrew and exchange the capsules, as needed). The 451 is a transformer-coupled mic preamp body that accepts a variety of detachable capsules, extension tubes and pads. The "E" suffix indicates an XLR connection; the "B" suffix indicates a bass roll-off switch with positions at 75hZ and 150hZ. Both of my capsules are cardioid, and sound relatively bright. The CK-5 is actually a CK-1 inside of a windscreen enclosure intended for use with vocalists (hence, the bass roll-off feature for proximity effect reduction). A fine acoustic guitarist is coming over tomorrow night to put the mics through the wringer. I'll report back later. When he heard about my acquisition, he couldn't wait to try them out!