I have a half track high speed Revox B77 I found on fleaBay. While this deck was NAB EQ, I also found a spare set of 3 3/4 - 7 1/2 NAB record and playback amp cards there, which were easy to convert to 7 1/2 - 15 CIRR. The slower speed NAB and high speed CIRR amps use the same PCBs, so it just required swapping a few caps and resistors. But the high speed NAB amps use different PCBs, so I couldn't just convert those.
So this deck is now fully capable of handling Tape Project tapes, and I played the one I have on it after a cleaning. It's on my workbench right now - I've now replaced the wear parts and did a full recap. Playback works fine, but I'm trying to track down why the left channel won't record before I button it up and put in back in my system.