Does the headphone jack or Main Out need pre-amped to go into an amplifier for regular speakers?

I need to come out of the 44VSL into a regular amplifier. I am recording a meeting where all mics are being recorded using software and the USB out to the computer. I need to use any of the outputs to go into an amp to be distributed to ceiling speakers. I have had no luck at using any of the outputs (as described in the manual) as line inputs on my amplifier. Please advise. Thank you