+1. You're asking for trouble any other way. Too many unknowns.
+2 Plus remember that powering sound gear from multiple non-inverter generators and utility power can result in some really strange sounding ground loop hum. The hum will be modulated by the difference in RPM between different power sources. For instance, if one generator was running at 59.9 Hz and the other was running at exactly 60 Hz, there would be a phase shift cancellation in the ground loop currents every 10 seconds. Not exactly what you want to hear. I always carry a few Hum Eliminators and ISO-2 boxes in my road kit for these ground loop situations.