High quality pro amps do not have a higher noise floor nor ANY compromise compared to home amps, except in cosmetics. The Yamaha P**00S series is such an example. They are dead silent. Have high power. They are fan cooled, but the fans never come on in normal use; you have to dog these amps to get the fans to activate.
The Yamaha series starts out at the P2500S, the lowest powered unit, which produces 250 watts x 2 into 8 Ohms, 20hz-20,000Hz, and 310 x 2 into 4 Ohms, 20hz-20,000Hz. They highest power one in this series is the P7000S, which outputs 700 x 2 into 8 Ohms, 20Hz-2000Hz, and 900 watts x 2 into 4 Ohms, 20Hz-2000Hz. They have two intermediate power level amps between these two extremes for your choose from. Do note: these amps expect a pro-level balanced input. If your pre-amp or active crossover(if you are usig one) does not provide this, you can use an inexpensive adapter to change the consumer level unbalanced source signal to a balanced pro-level signal. Failure to use the adapter box would result in possible audible noise floor hiss. This is because the consumer level signal is very low in voltage compared to the pro level signal. As such, you would have to use absurd level if input gain setting to get the signal to the desired level/SPL. FYI, the Yamaha amps are standard class AB output stage, but they have 90 percent efficiency, in contrast to standard AB class, where efficiency is 50-60 percent. This is due to the microprocessor controlled real-time variable power supply rails used in the Yamaha Pxx00S amplifiers. The amplifier varies the rail supply in real-time to what is needed. It is similar to Class H, I suppose, but instead of simply two rail voltage potentials, the Yamaha amplifiers vary it infinitely on a constant basis.
-Chris
