Parasound Halo A 23+ John Curl Design Stereo Power Amplifier

A Powerful Amplifier

High-end performance is provided by Parasound Halo A 23+ in a compact, rack-mountable chassis. This amplifier can drive almost any pair of speakers you could want to connect because it has a 160 watts per channel output and is steady at low impedance. It strikes with 500 watts into a single channel while in bridged mode. A large toroidal transformer and a Class A/AB amplifier with high bias are responsible for all of that power.

Operation in Class A/AB for a more rounded audio

Let’s go over the advantages of a Class A/AB amplifier as you don’t see them very often.

Class A designs are usually acknowledged by engineers and audiophiles to provide the clearest sound, although they can run hot and take up a lot of room. As a result, Class AB, a compromise that is frequently used in household audio amplifiers, transfers a portion of the audio signal to a different set of output transistors at high power levels. Although some signal purity may be lost when using AB, the amp will run more smoothly and effectively.

Thus, before the second set of transistors come on, this Class A/AB amp operates in pure Class A mode at a greater power level than the majority of other amplifiers in its price range. The end effect is a smoother, less taxing, and more organic sound.

Accessible connections

Each channel’s inputs—balanced XLR and unbalanced RCA—have a separate gain control knob and loop output on the back panel. Additionally, binding posts are available for joining a pair of speakers. The provided ears allow for rack mounting of the amplifier.

The John Curl legacy

The legendary audio engineering genius John Curl created the circuitry for the A 23+. His career began in the 1970s when he worked at Ampex creating tape and video recorders. He also contributed to the creation of the Grateful Dead’s renowned Wall of Sound. Since 1989, Curl has designed all of Parasound’s high-power amplifiers in addition to other products. The A 23+’s power supply, transistors, capacitors, and other components were selected to provide excellent performance at competitive prices.

• 160 watts x 2 @ 8 Ω RMS, both channels driven
• 240 watts x 2 @ 4 Ω RMS, both channels driven
• 500 watts x 1 @ 8 Ω, in bridged mode
• Circuitry designed by legendary John Curl
• High bias Class A/AB operation
• 45 amperes peak current per channel
• Stable with speaker impedance dips below 2 Ω
• Balanced inputs with discrete circuits
• Heavy-duty 24k gold-plated 5-way speaker binding posts
• Gold-plated RCA input & loop output jacks
• Direct-coupled signal path, no capacitors or inductors
• DC Servo and relay protection circuits
• AC turn-on inrush surge protection with relay bypass
• JFET input stage, MOSFET driver stage
• 12 beta-matched 15 ampere, 60 MHz bipolar output transistors
• 1.1 kVA shielded toroid transformer w/ independent windings for each channel
• Independent power supplies for input stage, driver stage and output stage
• 54,400 µF filter capacitors for output stages
• Full power is rated all the way down to 5Hz for unrestricted low-end bass
• Harris hyper-fast soft-recovery bridge diode rectifiers
• Automatic turn-on by 12 V trigger or audio sensing
• 2 rack space chassis with rear carry handles
• Rack mount hardware available separately
• Available in silver or black