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4.6Out of 134 Reviews

    • A 21+ Halo Stereo Power Amplifier
      • A 21+ Halo Stereo Power Amplifier
      • A 21+ Halo Stereo Power Amplifier
      • A 21+ Halo Stereo Power Amplifier
      • A 21+ Halo Stereo Power Amplifier
      • A 21+ Halo Stereo Power Amplifier

      Parasound

      Parasound A 21+ Halo Stereo Power Amplifier

      (0)

      $2,995.00

        In stock (0) - 10 - 20 days Available in store: Check availability

        The Halo A 21+ improves on the already over-the-top amazing Halo A 21 via carefully thought-out performance upgrades for cleaner, ultra-low distortion sound, revised front panel cosmetics, and a revised rear panel layout offering enhanced features, too.

        Product description

        Impressive Performance Upgrades

        The performance upgrades are impressive, beginning with a big 25% to 30% increase in output power compared to the previous model. The A 21+ delivers 300 watts-per-channel at 8 ohms compared to 250 watts-per-channel for the A 21, 500 watts-per-channel compared to 400 watts-per-channel at 4 ohms, and a huge 1,000 watts in bridged mono mode compared to 750 watts with the A 21.

        The performance of a power amplifier is highly dependent on the quality of its power supply, and Parasound went the extra mile with the A 21+, which boasts a 10% to 15% larger main power transformer compared to the previous model A 21. Transformer size has been increased from 1.2 to 1.3kVA, and the filter capacitance increases 20-30% from 88,000 uF for the A 21 to 108,000 uF for the new A 21+. You'll hear the advantages of these upgrades as the A21+ presents lower distortion at full power. In fact, signal-to-noise measurements have been upgraded from 115 db from the A 21's 112 dB. THD at full power is now a vanishingly low 0.1% compared to 0.2% for the A 21.

        Other performance upgrades include tweaked input circuits for improved crosstalk specs ( 70 dB at 20 kHz compared to 63 dB ) and upgraded internal gold on gold audio connections, resulting in a cleaner signal path that's also more reliable.

        Changes from The Original A 21→A 21+

        - 250 → 300 Watts ( at 8Ω )

        - 400 → 500 Watts ( at 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

        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 A 21 + Halo Stereo Power Amplifier User's Manual

        Specifications

        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: 175/8"
        Height without feet: 71/8"
        Height with feet: 73/4
        Depth: 20" 
        Depth with cables: 211/2

        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

        Contact us to inquire how you can finance your purchase through our partner, Synchrony.

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