The Bogen HTA250A Power Amplifier is a high performance unit employing Power MOSFET technology. The unique characteristics of Power MOSFETS make them ideally suited to power amplifier design, providing far superior performance and reliability compared to other types of transistors. They offer higher efficiency, reduced heat, simpler overall design, reduced size and weight. The Model HTA250A supplies 250 watts (rms continuous output) at less than 0.5% total harmonic distortion from 20 to 20,000 Hz. An input signal of only 500mV is required for full rated output. The input impedances are: high-impedance (50,000 ohms) unbalanced; low impedance (500/600 ohms, balanced or unbalanced) with optional accessory transformer Model TL600. Line bridging can be achieved with optional transformer Model TL100. Residual hum and noise is at least 90 dB below rated output and the output regulation is better than 2 dB from no load to full load. The HTA250A can drive a variety of load impedances. Outputs include 4 ohms, 8 ohms, 25VCT and 70 volts.The amplifier is capable of safely driving any recommended load continuously. The HTA250A is thermally protected to prevent damage due to excessively high temperatures; however, the amplifier will deliver the full rated output continuously, even at +49°C (+120°F). Additional failure-preventive devices include overload limiting, short circuit protection, and a Slo-Blo fuse. Electronic shutdown circuitry is automatically activated if an overload or short occurs and a front panel overload shutdown LED illuminates. Once the cause has been rectified, the unit automatically resets.The power on/off switch, located on the front panel, illuminates when power is on. The rear panel contains an input level control, input and output connections, the AC line fuse, and an auxiliary receptacle.A low-cut filter switch is located internally. *125W & 250W models. *Designed for continuous operation at rated power, up to 120 deg. F; convection-cooled. *Thermal protection and automatic electronic overload protection. *Hi-Z unbalanced and Lo-Z balanced or unbalanced input w/ accessory transformer (TL600). *4-ohm, 8-ohm, 25V, & 70V outputs.