If I got the 5400 it would be run via balanced cables into a Parasound JC-2 preamp.
If I got the Esoteric, I would use it direct without a preamp.
Both would ultimately drive a Pass Labs X250.5.
Currently this would be my only source--have not gotten into using my computer as a source yet but I like the idea of the SA-50's inherent flexibility.
The uncertainty is how the SA-50 would sound driving an amp directly vs running a 5400 through a good preamp. The reviews out there touch on the SA-50 preamp section briefly but not enough to get a thorough idea. Anybody run their SA-50 direct to amp?