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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

      $2,995.00

      • Article code: 063360

      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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