What pre-amp are you running now? Anything in particular you are looking for sonically or feature wise?
BAT gear seems to work rather well with Pass amps. My system is a baby version of yours (X150, VR2s) and have recently replaced a Pass X2 pre with a BAT VK3ix pre-amp with excellent results.
BAT gear seems to work rather well with Pass amps. My system is a baby version of yours (X150, VR2s) and have recently replaced a Pass X2 pre with a BAT VK3ix pre-amp with excellent results.