I just had some other thoughts on this one…. The VC7 was a dual mic preamp with switchable impedance matching for the microphones. I designed it as an exercise to produce the best possible sound out of a variety of microphones; it was a very ‘up market’ piece and worked brilliantly. It was also very expensive.
There is still a spec and some pictures of it on the original JoeMeek website, but it’s certainly not available now!
One notable feature of the VC7 was that it had a built-in M/S matrix designed for recording using a cardioid and a figure 8 microphone to achieve a complete stereo image from a single point. The thinking was not original, but it certainly led to my present work in amplifier and loudspeaker design.
Not enough use is made of that system in recording…. it’s possible to achieve superb depth and realism with no possibility of ‘hole in the middle’ problems.