In classical music, the so-called "Golden Age" was probably the mid-to-late 50s and early 60s, when companies were just starting in stereo, recorded in analog and didn't multi-mike or process the sound that much; as a result, recordings from that time had a more natural and realistic sound than later, when multi-miking, severe compression and digital recording became the rage. Recordings from Mercury, RCA, London/Decca and others from that period are often highly prized by audiophiles; hence the reissues that have come out generally are of recordings made in that era. There are some exceptions, of course, such as the Lyrita and Vox releases from the 70s, and Decca and EMI in my view maintained a high quality standard beyond the early 60s, but RCA (with its Dynagroove recordings) and Columbia/CBS and DG (excessive multi-miking and brightness) went downhill IMHO after that period in quality vinyl releases.
I don't know if there was a golden age for rock in terms of recordings--I tend there to think more of artists than recordings, but I'm sure others will give their thoughts on this and on jazz recordings.
I don't know if there was a golden age for rock in terms of recordings--I tend there to think more of artists than recordings, but I'm sure others will give their thoughts on this and on jazz recordings.