Active mixer and 180 degrees out of phase question?

Hello , i want to make a simple active mixer to place in front of the power amp.
I read some documents about active op-amp mixer.And they said :
"Any signal entering the inverting input of the op-amp will appear at the output but it will be 180 degrees out of phase.If the output of the first op-amp were recombined with one of the other signals at a later stage it would cancel out rather than mix. So we have to re-invert the phase with yet another op-amp."
and the schematic should like figure 1 to re-invert the signal .
But if i use the the mixer to direct feed input of power amp , can i use the schematic like figure 2(w/o re-invert the signal) ???

Thanks in advance!
Sorry for my bad English!

Picture of Active mixer and 180 degrees out of phase question?
You can use your second circuit. You'll get variable phase shifts at low frequencies, if your resistor values are too high, and your C values are too low.