Back when the AF SACD came out in 2015, Steve Hoffman referred to the '73 compilation as the "Paul Rothchild 1973 Quad attempt." I don't think there were pictures of the four-channel master included in the AF release or the more-recent Rhino Blu-Ray - so I suppose it's not 100% confirmed - but I'd take that as some indication Rothchild was involved.They were the original producers. The original quad LP credits only Botnick as the engineer, IIRC
https://forums.stevehoffman.tv/thre...adventures-in-mastering.428601/#post-12179730