from the PC to music fidelity v1 USB/SPDIF converter, to peachtree idac, to virtue sensation m901 integrated amp.
nothing's changed in the rest of the set up from when JRMC17 was working fine, what has changed is getting a 'buffering...' message on JRMC17 where the song details usually are.
Strangely it's worse with the imatched aac files - which read at 64bits/44.1hz when playing back, I find the 64 figure surprising.