Theoretically better to connect my subwoofer from preamp out, or from outputs on my amps?

I have the option to either drive my Mini DSP SHO subwoofer crossover/dsp from a second set of balanced outputs on my preamp, OR from the set of balanced outputs on my Parasound JC1+ monoblocks. I realize the obvious answer is to listen to both configurations, but I begin to  crossover at 35 HZ as my Sasha 2s play very low and I want to compliment them not truncate them with the crossover.  I choose not to run the mains signal though the crossover. This is why I say this is a theoretical question as I may not be able to hear the difference. (so maybe it doesn't matter, but its on my mind) I'm waiting on a pair of new cables so I can't test listen right now, but was wondering if there is a technical advantage to one approach over the other. I think this tangentially touches the REL sub wiring design theory as they seem to feel quite strongly that the mains and the sub should be seeing the same signal at the same time. Going in one cable socket on the amp then out another socket on the amp to a crossover DSP isn't exactly like the REL approach, but its similar in a way.  On the other hand sending the output to both the crossover and the amps at the same time makes sense too from a timing perspective. Parallel paths versus serial. You know how we can be when thoughts start swirling around in ones head! Just wondering if someone out there has thought about this already and/or has technical knowledge about the best approach.  Thanks for your time and thoughts.