The Golden Age of classical music was approximately late 50s to mid 60s. You can rack that up to very skilled engineers, especially DECCA, RCA, EMI, MERCURY, and tube electronics for recording and mastering. Solid state had some theoretical and even some practical advantages. (That’s why FAA went to solid state radios in the late 80s.) Some Beatles and Stones and others continued to use tube electronics into the 70s and 80s, you know, by the sound of it.
Recording during the 70's
Not sure if I'll get a response but all I can do is ask. It has been my understanding for many years now, that as the Recording Industry moved from tube equipment to solid state ... say from late 60's to late 70's, it took almost a decade for sound engineers to get "the bugs" out of the ss equipment which is why recordings from the 80's generally sound better than those from the 70's (let's put the common practice of over-modulation and the compression of dynamic range aside and I'm using rock as a reference). There were some exceptions however in the 70's, SuperTramp LP's for one (somehow wonderful recordings) and you will know others ... but there are many LPs from that decade that were just horrible ... love Jethro Tull's Agualung, but that album along with say, what Boston (another great group) put out .... terrible .... seem to be representative generally .... so much mush. Thanks for reading and replying.