I wouldn't ! The phono input will have massive gain compared to the line level inputs like 'cd' 'aux' etc etc It'll also attempt to apply RIAA equalisation to the signal coming form the iMac. + 20dB boost at ~20Hz, kittens/newlyweds and parrots could be harmed!
ah, cheers.
i will have a fnck around tonight to see if it is noisy on the phono. i don't think it is.
edit - using the 3.5mm out into the phono on the amp, until dac issues are sorted