If you happen to have an analogue tape that was originally recorded on a deck with a record-head that had a not perfect azimuth, i.e. the head was tilted, then that tape would play badly on a good analogue deck where the heads are positioned correctly. You would get phase errors and the treble playback would suffer a lot.
The analogue heads on a DCC deck (which btw are always perfect aligned in respect of the tape due to the ALP and FATG mechanisms) apparently don’t suffer that much from the problem with the high end of the audio spectrum. Because the head gap is so tiny, the angle does not matter that much as in conventional heads. The phase problem remains, however.
So it is worth to try old tapes with bad recording azimuth and see how they play on a DCC deck. I must admit I do not have much experience with this however.
But always keep the playing of ACC tapes to a minimum, because of the wear on the DCC heads and always clean the heads, capstans and pinch rollers immediately after playing.
-Philip.
EDIT: I read this somewhere, but now I can’t find it, yet.