Using the amp into the 4 ohm load: I would do it.I would start out easy, play music for awhile at moderate/low volumes and see how HOT the amp gets. The heat is the key. You know how hot it gets at the office. If it gets a LOT hotter just playing at moderate levels, then stop, bad.
If it is still just as warm, or even a little warmer, OK crank it up a bit, repeat.
The heat is a big indicator of being overloaded by low impedance.
If it is still just as warm, or even a little warmer, OK crank it up a bit, repeat.
The heat is a big indicator of being overloaded by low impedance.