In the world of four track pre-recorded tapes, the Deutsche Grammophon Releases made by Ampex have a higher ratio of poor quality reel to reel tape releases, as compared to some of the other record companies. Some of the poor examples are available on cassette and sound significantly better.
It would appear that Ampex was not rejecting low-grade transfers from the master and really should have stood their ground telling DG that they were not going to copy material that was so far away from the master.
Fortunately not all the tapes are this way but DG releases have a higher ratio of poor copies than other similar labels like London or Philips.