Unpacking the Parasound HALO A21+ Power Amplifier Review
In our Parasound HALO A21+ Power Amplifier Review, we explore how this heavyweight two-channel amplifier delivers an astonishing 300 watts per channel into 8 Ω and 500 watts into 4 Ω with less than 0.1 % THD. Designed by John Curl, the HALO A21+ marries high-bias Class A/AB operation with a direct-coupled signal path, preserving absolute transparency from 5 Hz to 100 kHz.
Design & Build Quality
The HALO A21+ sits in a robust 4-rack-space chassis featuring refined Halo cosmetics, aluminium end caps and gold highlights. At 32 kg, its reinforced steel frame and rear carry handles underscore serious build integrity. Updated gold-on-gold internal audio connections and heavy-duty JC5 binding posts add both durability and a touch of elegance to any rack.
Performance & Sound Signature
Switching from the original A21 to the A21+ brings power upgrades across the board: 300 W → 300 W (8 Ω), 500 W → 500 W (4 Ω) and a bridged single-channel rating of 1,000 W into 8 Ω. With a staggering 60 A peak current per channel and 108,000 µF of filter capacitance, this amplifier easily navigates speaker impedance dips down to 1.5 Ω. The result is rock-solid bass extension, ultra-low noise (115 dB S/N) and a neutral, uncoloured midrange that retains every nuance of your favourite recordings.
Key Features
- 300 W × 2 @ 8 Ω, 500 W × 2 @ 4 Ω (0.1 % THD)
- 1,000 W bridged mono @ 8 Ω
- High-bias Class A/AB topology (16 beta-matched output transistors)
- Direct-coupled signal path (no caps or inductors)
- Balanced XLR and unbalanced RCA inputs + loop output
- Independent input, driver and output power supplies
- 60 A peak current, 130 V/µs slew rate, 5 Hz–100 kHz bandwidth
- Auto turn-on by 12 V trigger or audio sensing
System Integration & Versatility
With both balanced and unbalanced inputs, plus A/B speaker terminals, the HALO A21+ is effortless to integrate into a wide array of systems—from full-range floor-standers to hybrid active/passive setups. We recommend pairing it with speakers rated down to 2 Ω for maximum dynamic impact and control. For detailed compatibility advice, visit the product page or speak with our experts.
Pros & Cons
Pros
- Outstanding power reserve and headroom (300 W/500 W continuous)
- Exceptionally low distortion (< 0.1 % THD at full power)
- Wide bandwidth and neutral tonal balance
- Sturdy build, refined cosmetics with gold highlights
- Flexible inputs/triggers for seamless integration
- Direct-coupled design for ultimate transparency
Cons
- Hefty 32 kg chassis may require a sturdy rack or stand
- No 4 Ω bridged operation—limited to 8 Ω in mono bridged mode
Why the HALO A21+ Stands Out in a Competitive Field
Few amplifiers at this price point deliver such a potent combination of power, precision and build quality. From thunderous low-end articulation to crystalline highs, the HALO A21+ is an audiophile’s dream. Whether you’re driving demanding tower speakers or experimenting with bi-amped setups, this unit never breaks a sweat.
Ready to experience the Parasound HALO A21+ for yourself? Speak with our HiFi experts at 1300 308 711 or email sales@theaudiotailor.com.au for personalised advice and a tailored demonstration. Elevate your system with our award-winning service and Australia’s highest-rated HiFi team.
