YAMAHA P3500S POWER AMPLIFIER The "P" series power amplifiers by Yamaha not only provide the user with excellent cost per watt value, they build on that cost performance with efficient power consumption. Utilizing Yamaha`s new EEEngine technology, these amplifiers deliver outstanding sound quality with remarkable efficiency. All of this power and performance comes in a compact 2U rack-mount size that makes installation and transport easy. If you need transparent amplification with excellent reliability and superior performance, give the "P" series a closer look. P3500S 390W St 8 ohms, 590W ST 4 ohms, 1180W Mono Bridge.