What is a Home Theater Bypass

Out of curiosity, is the Cary unit the only one with true bypass? In other words, not unity gain?

I have considered the high end HT processor option but HT technology evolves so quickly that within a year or two, it will be obsolete (HT-wise) and need replacing, whereas a stereo preamp with true HT bypass can be kept in place until the upgrade bug hits (hopefully a long, long time later). To me, therefore, a better (mostly because it is more cost effective in the long run) solution is a pre-amplifier with true HT bypass.