Harmonic distortion at higher signal levels

[chipaudette]

When using the new SD Player, I hear harmonic distortion whenever the total playback amplitude approaches -6 to -4 dBFS. The onset is very sudden.

I've been using a RevE with an earpiece shield. More testing is needed to establish whether (1) it is just the earpiece shield or also the Tympan, and (2) whether it is all Tympans or just this one unit that I have.

Recording to the SD card shows clean signals, so it must be something occurring in the output I2S class or in the AIC