Indeed, I believe all of the above mentioned pre's have "bypass". I am familiar with the LS16 AR preamp, which has the "bypass" as well. And yes, you simply use your volume control on your pre/pro in "bypass" mode on your preamp. Infact, it's usually the only way to control volume with this feature. You can use a dirrect auxilary input on many preamps for a pure pass through, with gain availble. You simply set the pre at around 12oclock, and use the pre/pro's volume. Still, the best is to use "dirrect bypass" and similar.
I used to run the L/R out's of my AV pre/pro into my passive 2 channel preamp's auxilary input, and it was superb! So there are options. good luck
I used to run the L/R out's of my AV pre/pro into my passive 2 channel preamp's auxilary input, and it was superb! So there are options. good luck