AppleTV work with USB DAC?

AppleTV can be "hacked" to enable USB output, but I believe it's more than software changes. I use my AppleTV with a VH Optocoupler II toslink cable to a Peachtree Nova Sabre Dac, and that is extremely good. If your DAC is USB input only, my suggestion is of no use..of course.

Don't think it can be done. BTW, the ATV does have a fan, when you pull the plug you can hear it spool down. I currently have an ATV connected through optical to a Theta TLC and then to a DAC and am happy with the sound. My main issue with the ATV is it very frequently hangs up and needs to be restarted, in particular after getting the new version of Front Row. Thinking of the Mini but it doesn't sync the same way as the ATV to use the Remote and has HDMI/component so video out is pretty straight forward. Now if I could only get a combination of the two.

Don't think a USB DAC can be used on Apple TV. I've used the ATV with excellent results thru a Benchmark DAC1. Unless you are up to doing serious mods, it's probably best to use optical out.

***On a side note, I read in a forum about a couple audiophiles who built a capacitor filter fob that plugged into the USB plug and added additional filtering to the 5v line. Apparently both the toslink transmitter and usb share the line so the extra capacitance on the 5v line contributed to better sound out of the toslink output. Basically it looked like a thumbdrive, but contained capacitors instead and only used the 5v line, not the signal lines.