Halo A 51

About the Halo A 51

The Parasound Halo A51 is a five-channel power amplifier designed by legendary John Curl, featuring THX Ultra2 certification for home theater excellence. It operates with high-bias Class A/AB circuitry, delivering 250 watts RMS per channel into 8 ohms and 400 watts into 4 ohms, all channels driven. The amplifier uses a 2.2 kVA encapsulated toroidal power transformer with independent secondary windings for each channel and a massive 164,000 µF power supply filter capacitance, providing a peak current capacity of 60 amperes per channel. Its direct-coupled design eliminates capacitors and inductors in the signal path for maximum purity. The complementary MOSFET driver stage and JFET input stage, along with 40 beta-matched 15 amp, 60 MHz bipolar output transistors, ensure exceptional sound clarity and power handling. Features include balanced XLR and gold-plated RCA inputs, a ground lift switch, heavy-duty 24k gold-plated 5-way speaker terminals, and auto turn-on via 12V trigger or audio signal. The amplifier also includes DC servo and relay protection circuits, along with indicators for AC presence, channel status, and temperature. Its robust 4U chassis includes rack mounting hardware and carry handles, weighing 80 lbs. The Halo A51 is praised for its uniform power delivery across all channels, low distortion (<0.2% THD), high signal-to-noise ratio (112 dB), and wide frequency response (5 Hz to 100 kHz). It is suitable for demanding home theater and high-fidelity audio systems, providing both musicality and dynamic power.