Newbie question: I plan to get two UPA-1s (or maybe an XPA-2) and had been planning to get the USP-1, but now I'm wondering whether the XDA-1 would be a better choice. My only source is a CD player and I have no interest in LPs. Is there any reason to still choose the USP over the XDA (especially when the XDA is $100 less)?
It comes down to how you plan to connect your sources. If you want to connect your CD player thru a digital interface, then get the XDA-1. If you're connecting thru an analog interface, get the USP-1.
If you think the DAC in the XDA-1 will be superior to the DAC in your CD player, get the XDA-1. If you think the DAC in your CD player is superior, get the USP-1.
One additional consideration is whether you have full range speakers for reproducing the bass frequencies. If your speakers are not capable of reproducing frequencies down to the mid thirties, you may want to get both the XDA-1 and the USP-1. You would feed the signal from the XDA-1 to the USP-1 to give you analog bass management. This assumes you do not have a dedicated amp and sub woofer to feed the XDA-1's signal to. The USP-1 will allow you to seamlessly share your HT amps, speakers and sub woofer using the HT Bypass switch.