Just to make certain that I was not out of my head prior to ditching the Pass preamp, I inserted a borrowed McIntosh C2300 into my system to see how it would behave. Even with the "homogenized" sound profile of the Mac Preamp, the Pass amps came to life.
Consider this...I(personally) have never heard(or read) of anyone using a Pass preamp with amps other than that of Pass. If they were truly any good, one would think that you would learn of more people using them in non Pass amp applications...