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

Parasound Halo A21+ Stereo Power Amplifier

C$4,500.00Price
  • Power Output – Stereo Mode (0.1% THD)
       300 watts x 2, 8 Ω both channels driven
       500 watts x 2, 4 Ω both channels driven

     

    Power Output – Bridged Mode (0.1% THD)
       1000 watts x 1, 8 Ω

       Bridged 4 Ω operation is not recommended

    Power measurement are at 120 VAC:
       0.1% THD, RMS continuous power,
       full audio band (20 Hz - 20 kHz)

     

    Current Capacity: 60 amps peak, per channel

     

    Slew Rate: > 130 volts per microsecond

     

    Frequency Response
       5 Hz - 100 kHz, +0/-3 dB
       20 Hz - 20 kHz, +0/-0.25 dB

     

    Total Harmonic Distortion (THD)
       < 0.1 % at full power
       < 0.03 % at typical listening levels

     

    IM Distortion: < 0.04 %

     

    TIM: Unmeasurable

     

    Inter-channel Crosstalk
       > 80 dB at 1 kHz
       > 70 dB at 20 kHz

     

    Input Impedance
       Unbalanced: 33 kΩ
       Balanced: 66 kΩ,(33 kΩ per leg)

     

    Total Gain: 29 dB

     

    Input Sensitivity for 28.28 V Output into 8 Ω
       Unbalanced: 1 V
       Balanced: 1 V per leg

     

    S/N Ratio
       > 115 dB, input shorted, IHF A-weighted
       > 110 dB, input shorted, unweighted

     

    Damping Factor: > 1100 at 20 Hz

     

    DC Trigger Requirements: +9 Vdc to +12 Vdc, 5 mA

     

    Audio Trigger Requirements: 2 mV - 10 mV

     

    XLR Pin Identification
       1 = Ground (Shield)
       2 = Positive
       3 = Negative (Return)

     

    Dimensions
    Width: 17-5/8" 
    Height without feet: 7-1/8" 
    Height with feet: 7-3/4" " 
    Depth: 20" 
    Depth with cables: 21-1/2" 

     

    Net Weight: 71 lb. (32.2 kg)

     

    Shipping Weight: 88 lb. (39.9 kg)

     

    Power Requirement
       Standby: 1 Watt
       Idle (no music playing): 160 Watts
       Typical Listening levels: 300 Watts
       Maximum: 1400 Watts