Parasound Halo A 21 Amplifier Review
Parasound Halo A 21 Amplifier
Summary
- Product Name: Halo A 21 Amplifier
- Manufacturer: Parasound
- Performance Rating:
- Value Rating:
- Review Date: October 19, 2004
- MSRP: $2000
- Specifications
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- Circuitry designed by legendary John Curl
- THX Ultra 2 certified
- High bias Class A/AB operation
- Balanced inputs with discrete circuits and XLR connectors
- Direct Coupled - no capacitors or inductors in signal path
- Complementary MOSFET driver stage and JFET input stage
- 16 beta-matched 15 amp, 60 MHz bipolar output transistors
- 1.2 kVA encapsulated toroid power transformer with independent secondary windings for each channel; 100,000 µF power supply filter capacitance
- DC Servo and relay protection circuits
- AC present, channel status, high temperature indicators
- Gold-plated RCA input jacks, loop output jacks
- Heavy-duty 24k gold-plated 5-way speaker binding posts
- Auto turn-on by 12v trigger or audio signal, 12v trigger out
- Rear panel gain controls; ground lift switch
- 4U Chassis; carry handles; rack mounting adapter included
- Parasound's 10 years parts, 5 years labor warranty
- Continuous Power Output: 250 watts RMS x 2, 20 Hz - 20 kHz, 8 ohms, both channels driven; 400 watts RMS x 2, 20 Hz - 20 kHz, 4 ohms, both channels driven; 750 watts RMS x 1, 20 Hz - 20 kHz, 8 ohms
- Current capacity: 60 amperes peak per channel
- Power bandwidth: 5 Hz - 100 kHz, +0/-3 dB at 1 watt
- Total harmonic distortion: < 0.2 % at full power
- IM distortion: < 0.04 %
- Slew rate: >130 V/µsecond
- Dynamic headroom: > 1.5 dB
- Interchannel crosstalk: > 80 dB at 1 kHz; > 63 dB at 20 kHz
- Input sensitivity: 1 V for 28.28 V, THX Reference Level
- Input impedance: 33 kW unbalanced; 66 kW balanced
- S/N ratio: > 112 dB, input shorted, IHF A-weighted
- Damping factor: > 1100 at 20 Hz
- Voltage: 110V - 120V
- Dimensions: 17-1/4" w x 7-5/8" h x 19-1/8" d, 7" h without feet
- Net weight: 60 lbs
Pros
- Bridgeable Channels
- Balanced and Unbalanced Inputs
- Diversified features
- Exceptional Build Quality
- Multiple "power on" options
Cons
- Two amplifiers required for 7-channel audio (A 21 and A 51)
- Increased cost associated with two amplifiers
Introduction
At first look the Parasound Halo A 21 is an appealing and robust amplifier accented by brushed metal finish and a "Halo" aqua blue light around the power button. But an amplifier is not just about cosmetics especially when considering that most Audio Enthusiasts seem more interested in sound quality and features. The A 21 amplifier is both loaded with usable features above and beyond most other amplifiers in today's market.
- Halo A 21 Amplifier Build Quality
- Halo A 21 Amplifier Build Quality - Continued
- Halo A 21 Amplifier Listening Tests
- Halo A 21 Amplifier Measurements & Conclusion
