Yeah on the PCM.
Here are a couple suggestions to look at that could use you attached USB drive (if it is self powered).
Sonore Sonicorbiter SE. ~ $350
BlueSound Node - ~$500
Cambridge Audio CXN ~$1,000
Rapsberry PI with Volumio~ ~$200
All but the Cambridge would need a phone or tablet for control. The Cambridge has a screen and remote.
Please note I have not used any of these personally. But I know they have the functionality that would work.
Excellent, thank you! That's the pricing I was hoping to be in. I'll check them out and see what works for me! All my HDDs are self powered.