c-11 pre amp

I have a a c-11 pre amp. Currently I have been using the c-11 with a pm-600 amp. I have in the past used an electronic crossover for using the pm 175 and pm 600 with the c-11.

Recently I disconnected the electronic crossover. I have found I connect ed each amp to one of the two outputs, "main 1" and the other to the "mani 2" . Of course I connected the oringinal factory crossovers back to the speakers within the enclosures. They both seem to work fine and sounds pretty good.
Question is, what exactly is happenning with the pre amp with both of these amps connected . The pre amp must be a "dual" pre-amp to do this correct? All the treble and bass controls work fine with this set-up for both amps. So I would like to know the scenario or overview of what is happening with this set-up using the c-11 to control both amps at the sametime(pm-600 connected to main 1 & pm-175 connected to main 2). What effect if any does it do with total amp values when connected like this? etc.
Any negatives for doing this?

thanks

It is doing what it was designed to do. Control both amps at once. A useful feature for bi-amping speakers.

soooo, I could use one of the mains to a power subwoofer?

YES!!!! I do that with my C-11. If you are using a powered sub connect directly as you would an amp. If using one of your amps, just run it to the non powered sub.

Any negatives using this set up with two amps?

Not any I'm aware of. Why would you think there would be a disadvantage??? This is what it was designed to do...

Possibly lack of control, separation between amplifiers, gain adjustments? As far as sound derogation, the unit was designed with that use in mind, as stated above, so no, there shouldn't be any unless there's something wrong with the unit.

He is using 2 pro amps so I know that they have separate gain controls for each channel so that should not be a factor...

Yes as far as gain control , the amps have them. But my wife probably will ask that the pre amp volume gain control be lowered when shes enters the room. Ha