First of all, relax dude! I suggest reading the manual again. Although it does come out and say your answer word for word, you can easily run only one speaker with this amp head. The unit is going to power the channel you are using based on the signal you feed it. The power amp you have and nearly every other PA style power amp around are comprised of MOSFET power sections, this is not a tube power sections. A tube amp has to put out power otherwise it will burn itself out. MOSFET power sections (basically everything out there not containing tubes) will be fine without powering a cabinet even though you are feeding the unit a signal.
Have you checked out the sensitivity switch? You can move that switch around & maximize the signal coming from your pre-amp. The stronger the signal, the better the sound going into the power amp and the better it will sound for you.
Seems like a really nice power amp! Enjoy it! If you are having trouble understanding the rest of the manual, post the confusing sections on here and ask for a better explanation. We will help you!
