How can I improve Apple iTunes through my system?

I would recommend either a high-end sound card, like the ESI U24. It's external USB and works with MACs and PCs. The other option would be to send the SPDIF signal to a high end DAC. The later would probably be the best (you can spend a good $10k on a DAC if money is no object) but the ESI cards are very good.

Go to preferences and turn off all the effects. Leave the volume control on the main screen all the way up (to the right) and don't change the volume or add EQ for individual songs by using the Info/Option control. Since the G5 comes with a built in optical digital out, you should connect it to an external high quality D/A. If you want, you can add a jitter reduction device between the G5 and the D/A.

Awesome! A bunch of Mac users, G5ers to boot!

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