Since upgrade, optical out does not work

Unpower it and restart if you haven't done so already.

OK, that sometimes kicks the optical port into submission 😝 but not here.

Is this stereo or 5.1 content?

Is the amp configured for Auto or 5.1 on that optical input?

I have a theory that a recent update caused the AppleTV to analyse what the HDMI connected device could decode and if it was stereo linear PCM only that too gets output over optical - if the amp is expecting 5.1 it won't handle the linear PCM. Try changing teh Dolby Digital out settings on AppleTV - try forcing Dolby Digital On rather than Auto if you are trying to get 5.1 sound - that may prevent stereo audio over HDMI however.

AC

I'm assuming you've tried another optical cable/input if you have one. With the optical lead plugged into AppleTV do you see ared light at the other end?

Strange, I also assume you've tried a variety of material with and without dolby digital.

Next step really would be to restore to factory settings and failing that working factory restore the unit via iTunes to replace the current firmware in case it's corrupted, as described here:

http://support.apple.com/kb/HT4367?viewlocale=en_US&locale=en_US

Also if the AppleTV is under warranty consider a warranty replacement/repair.

AC

Have you been able to test the optical input on the amp with another device eg DVD player?

Warranty?

There;s a 12 month warranty, use it if you can 🙂

Huntingheads, did you ever get this resolved?