Battery Life seems to be something our competitors have forgotten. As long as it lasts long enough for one event seems to be their mantra. Not us here at Amplivox though! We have engineered our products to consume the smallest amount of power possible without compromising sound. Our SW805A Amplifier has the best battery consumption of any PA Amplifier in the industry with 200+ hours of operation with 10 D-Cell Batteries. When it comes to rechargeable batteries of course the battery life is dramatically lessened, but we have made great strides at increasing the battery life of our rechargeable systems.
Most notable is that our Digital Audio Travel Partner runs 30 hours on a rechargeable battery. For a 250 Watt PA System to last 30 hours on one battery charge is simply unheard of. Even more astounding is the fact that it has a digital preamp, and a wide array of features and yet it still out performs other systems.
How does it do this? It is designed with a Class D Amplifier that dramatically increases its efficiency. Because of this higher efficiency, no large heatsinks and transformers are needed which corresponds to a lowering of product weight as well. A class D Amplifier works in this way...
"The input signal is converted to a sequence of pulses whose averaged value is directly proportional to the instantaneous amplitude of the signal. The frequency of the pulses is typically ten or more times the highest frequency of interest in the input signal. The output of such an amplifier contains unwanted spectral components (that is, the pulse frequency and its harmonics) which must be removed by a passive filter. The resulting filtered signal is then an amplified replica of the input." (See wikipedia article at http://en.wikipedia.org/wiki/Class_B_amplifier#Class_B_and_AB). Our circuitry is designed with high quality sound and drastically reduced power consumption in mind.
Our amplifier uses a pulse width modulatation scheme, but with many Improvements over most of the class D implementations. These include...
-All of the power converters are synchonized. This prevents beat frequencies and noise from getting into the system.
-The ramp generator for the PWM is extremely linear reducing distortion.
-The control loop is designed to operate in a closed loop mode for low frequencies where there is the most signal power and highest likelyhood for distortion and then it shifts to an open loop mode at high frequencies. At high frequencies, the distortion components wind up outside of the human hearing range and the signal power is lower.
Before you find yourself frustrated with a competitor's product running out of power at the end of their presentation, consider Amplivox as your source for Portable PA Systems.