although i prefer vintage tubes, the tube circuit is critical in revealing or not revealing the differences in performances between current production and older tubes.
i just spoke to lyric hifi regarding the mcintosh 2102 amplifier. i am looking for an amp, cd player and preamp--all tubes, and have been considering mcintosh products.
i was told that the 201 does not change its sound when the driver tubes are replaced. i am also considering the c 220 preamp. it may be relatively insesentive to tube changes as well. certainly, my bat vk d5 cd player hardly changed sonically when i used amperex and mullard 6 volt tubes.
the bottom line: a difference makes no difference if you don't hear it. many of the current generation of tube products are designed around current tubes and are not responsive to changes in tubes.