To answer a number of accumulated questions:
Schoeps KC -- cables have fixtures on each end: one for the capsule and one for the amplifier. There's really no way to extend such a cable.
- For a few years Schoeps sold KC cables with Lemo plugs that allowed an extension cable to be added in, or the Lemo could be plugged into an adapter that screwed directly on to a CMC amplifier, or there was a neat little mixer that up to four of the Lemos could be plugged into (back then, Schoeps also made lavalier microphones with Lemo outputs, so they could be mixed via those mixers as well--see flyer below; at the moment I can't seem to find it in English, but if anyone has questions, let me know). -- The Lemos were fiddly and the mixers were expensive and didn't sell well, so the whole Lemo adventure came to an end within a handful of years. They are not missed.
A KCY is like a pair of
just the capsule ends of two KC cables, which join together in a little junction box and terminate in a Binder plug. Please see
http://schoepsclassics.de/1989_compact_system.htm - the plug end of a KCY could be plugged into a VST 62 stereo amplifier (body), any of a number of VMS preamps, a Lemosax preamp, or certain highly regarded homebrew preamps that are sold on this forum. But the KCY doesn't have fixtures for a pair of CMC amplifiers. For that you'd need to attach an AKI 2C, which is a Y cable that goes "in the opposite direction" and has a Binder socket input, a junction box, and two cables that terminate in fixtures that fit onto CMC amplifiers. You can then run a Binder-to-Binder extension cable between the two Y cables, but the total length of that cable should be kept reasonable, since it's all unbalanced.
I don't know of any extension cables that run between a condenser microphone's capsule and amplifier that are balanced. They aren't intended for use in high RF environments by today's standards, especially if multiple cell phones are right near the capsule or the cable. If that's a concern, I suggest the Schoeps CCM series although it isn't modular.
For that matter, most "active" cables, other than those from Schoeps, aren't even really active--they contain no circuitry that provides gain. I've complained for years about the misuse of the term "active", but only some people have taken it to heart.
--best regards