KPO Pointers - Power ams have several ratings that must be understood to establish the amps quality. Most of us are familiar with Watts a measurement of the power an amp produces. Power amplfiers also have ratings such as minimum Ohms (how many speakers can be put on the amp) and slew rate (how quickly the amp responds). Another important spec is damping factor especially important for an amp running Subs. The damping factor is the measurment of the amps ability to control the speaker. The bottom line when considering a power amplifier is the reputation of the company producing the amp. Something to consider is does the amp have UL (Underwriters Laboratories) certification. UL perform rigorous testing to support published specs. If the amp has no UL sticker the manufacturer can publish any spec they want. Crown, QSC. EV and Peavey have UL certified specs.