DG had a lot of really good sounding stuff back when they had the so called tulip label. Was that in the 50s and 60s?Yes, the records with the tulips on the label are considered to be the higher quality recording period; 50s and 60s.
http://www.micrographia.com/projec/projapps/viny/viny0000/dggold.htm
The 1960’s recordings into the early 70’s are very good sounding stereo. It seems to me after DG became part of Polygram, their sound quality suffered.
But Decca and Mercury Living Presence were always superior in SQ.