Parasound Halo A21+ Stereo Power Amplifier by John Curl

  • $4,500.00


  • Changes from the original A 21→A 21+

    • 250 → 300 Watts (8Ω)
    • 400 → 500 Watts (4Ω)
    • 750 → 1000 Watts (bridged)
    • Filter cap: 88,000 uF → 108,000 uF
    • S/N: 112dB → 115 dB
    • THD (at full power): 0.2% → 0.1%
    • Crosstalk (20kHz): 63dB → 70dB
    • Transformer size: 1.2 kVA → 1.3 kVA
    • Weight: 60 LB → 71 LB
    • Refined Halo cosmetic with aluminum end caps & gold highlights
    • Updated rear panel with heavy duty speaker terminals from JC 5
    • Upgraded internal gold on gold audio connections
    • Updated auto turn on circuit

    All Features

    • 300 watts x 2 @ 8 Ω RMS, both channels driven
    • 500 watts x 2 @ 4 Ω RMS, both channels driven
    • 1000 watts x 1 @ 8 Ω, in bridged mode
    • Circuitry designed by legendary John Curl
    • High bias Class A/AB operation
    • 60 amperes peak current per channel
    • Stable with speaker impedance dips to 1.5 Ω
    • Balanced inputs with discrete circuits
    • CHK Infinium, custom 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
    • 16 beta-matched 15 ampere, 60 MHz bipolar output transistors
    • 1.3 kVA shielded toroid transformer w/ independent windings for each channel
    • Independent power supplies for input stage, driver stage and output stage
    • 108,000 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
    • 4 rack space chassis with rear carry handles
    • Rack mount hardware is included
    • Available in silver or black