PentaTone (actually, Polyhymnia, PentaTone's engineering provider) did indeed do a good job with these quad recordings, which I produced. They did so simply by keeping their fingers off the knobs while making the transfers to DSD from the 4-track analog masters, just as they were when I left them in DG's Hannover post-productions studios 40-some years ago. The Polyhymnia engineer Jean-Marie Geijsen confirms that in no uncertain terms here:
https://www.youtube.com/embed/GBctVE8qGEs The buyer of PentaTone's SACDs will hear exactly what we made back then.
- Thomas Mowrey, New York, 4/23/15