Parasound Halo A-51 Silver 5 channel Amplifier
The A51 power amplifier combines raw power with elegant circuit design. Designed by legendary audio guru John Curl in collaboration with CTC Builders, the Halo brings uncompromising audiophile performance to home theater. Matched JFET inputs, MOSFET drivers, and high-current bipolar outputs contribute to its exceptional performance. Class A / AB Operation and Impressive Firepower The A51 boasts balanced inputs with discrete circuits and XLR connectors. Beautifully implemented high-bias Class A / AB operation makes the most of an impressive 250-watt-per-channel power output at 8 ohms and 400-watts-per-channel at 4 ohms. The 2.2 kVA encapsulated toroidal power transformer with independent secondary windings for each channel and 164,000 µF power supply filter capacitance delivers an impressive current capacity of 60 amps per channel. The direct-coupled design uses no capacitors or inductors in signal path. The complementary MOSFET driver stage relies on the firepower of 40 beta-matched 15 amp, 60 MHz bipolar output transistors and works in combination with a JFET input stage. The A51 has Parasound’s exclusive bias circuit, which permits the amplifier to sound perfect from the instant it’s turned on, rather than having to wait for bias to gradually build up as the amp warms up over time. Very high bias allows greater Class operating range than others. Even Halo’s implementation of its automatic turn-on feature is exceptional. Special relays bypass the AC “soft start” circuitry after it’s done its job for the purest AC and the purest sound. “Instant” Warm-up Feature. AC present, channel status, and high temperature indicators team up with DC Servo and relay protection circuits to keep this powerhouse running safely at peak performance for years of reliable service. Auto turn-on by 12-volt trigger or audio signal simplifies home theater and multi-room operation. Other features include heavy-duty 24k gold-plated 5-way speaker terminals, gold-plated RCA input jacks, and a rear-panel ground lift switch.