Parasound Halo A 21+ Stereo Power Amplifier

A 300 W, high-bias class A and AB amp designed by John Curl. Can be bridged for 1,000 W mono.

With circuitry designed by the legendary John Curl, the Parasound Halo A 21+ is a hugely powerful high-bias class-A with AB operation that delivers 60 A peak current per channel. It will drive even speakers whose loads dip below 1.5 ohm. It has balanced inputs with discrete circuits, and the direct coupled signal path means no capacitors or inductors get in the way of great sound.

The JFET input stage is connected to a MOSFET driver stage, and the amp uses 16 beta-matched 15 ampere, 60 MHz bipolar output transistors. The 71 lb. amp uses a 1.3 kVA shielded toroidal transformer with independent windings for each channel. There are independent power supplies for the input, driver, and output stages. The output stage uses 108,000 µF filter capacitors. Harris hyper-fast soft-recovery bridge diode rectifiers continue the theme of expensive, overspecified design that results in a sound with huge power and headroom. Full power is rated all the way down to 5Hz for unrestricted low-end bass

Features

• DC Servo and relay protection circuits
• AC turn-on inrush surge protection with relay bypass
• Automatic turn-on by 12 V trigger or audio sensing
• 4 rack space chassis with rear carry handles
• Rack mount hardware included

Specifications

Power Output (8, 4, 1 ohm): 300 W, 500 W, 1,000 W

Inputs: Stereo RCA, stereo XLR, DC trigger

Input Impedance (Bal., SE): 66 kΩ, 33 kΩ

Gain: 29 dB

Dimensions (WHD): 17-5/8″ x 7-1/8″ x 20″

Weight: 71 lb.