I should have mentioned a couple of things while this thread was fresh:
1. The polarization voltage of a C60 is about 15-20 VDC below that of a C12/ELAM 251/C414, or any other AKG mic that was designed to drive the CK12 large diaphragm capsule, which needs 60VDC to operate quietly, and to achieve its full dynamic potential. I.e. under-powering a capsule spec'ed for 60VDC with too little polarization voltage, the mic gets too noisy.
2. Contrary to common belief, The CK4 did not come with the famous brass CK12, but the later, 'Teflon' CK12, as used in the C414 B ULS- a rather gray and unexciting affair.
AKG never bothered to rename that new capsule to avoid confusion (or maybe also naming the new capsule CK12 was intentional, to suggest no drop in the quality of sound).