If the pre-echo is for the groove, you will here it right one LP turn before the "real" sound is played. If it's for the tape, as derek said, the relation isn't that linear since the tape turns don't match the LP groove turns.
On a ECM recording I wouldn't expect it to be from tape print-through, I don't think they had the master tapes stored long enough to have that effect -if that exists which I really doubt- but for groove rims being too thin. The effect is more noticeable when a recording hasn't much dynamic compression and a high SPL turn is right following one with quiet levels.