Both amps are very good. My tastes lean more toward the Pass X350. The presentation is a bit different than the 336 and it seems to be a bit more natural. Niether would be a bad choice.
As far as CD players, save for the Audio Aero Capitole 24/192. From my comparisons, it is currently the pinnacle of PCM digital. One of the special things about the unit is the remote driven volume control. I have taken out my preamp and the sound was greatly improved. If all you use is digital, you could probably sell your preamp and CD player and improve your system with little or no out of pocket expense.
As far as CD players, save for the Audio Aero Capitole 24/192. From my comparisons, it is currently the pinnacle of PCM digital. One of the special things about the unit is the remote driven volume control. I have taken out my preamp and the sound was greatly improved. If all you use is digital, you could probably sell your preamp and CD player and improve your system with little or no out of pocket expense.