I've recorded some (higly repetitive) music with my A807 on three of its four speeds. I couldn't do 30 IPS (76,2 cm/s) as I don't have a calibration tape for that speed, so I can't calibrate the machine. Listen yourself how do different speeds compare to each other and also to the original source file. The recording was not edited in any way other than cutting and volume adjustment, so the loudness won't mislead you. No noise reduction or any kind of other wizardry used during recording, playback or editing in digital form.
Tape: Maxell UD XL50-120B