I helped Dietrich with breaking down the mastering studio this 670 came out of. It was owned by an engineer named Claude Rei. The studio was set up in 1965 by Albert Grundy. Claude Rei passed on in 1968 an an early age. The studio was in his basement and his widow has lived in the house ever since.
This studio was the best of everything. It had a Neumann AM132 lathe with a stereo Ortofon drive package. Custom Ampex 300's with a preview path and custom made repro amps made by Al. There was also another pair of stock Ampex 300's. 670's, pultecs, Fairchild high frequency limiters which were new to me. All sorts of other custom made stuff too. Just incredible.
I wanted to see it because it was Al's work at the top of his game.