Halo reference multi-channel power amplifier • circuit design by legendary engineer John Curl • high-bias Class A/AB operation • 250W RMS x 5 into 8 Ω / 400W RMS x 5 into 4 Ω • 2.2 kVA encapsulated toroid power transformer • 60 amperes peak current per channel • THX Ultra2 certified
The Parasound A51 Five Channel Power Amplifier stands as an enduring benchmark in reference multi-channel amplification, designed by audio legend John Curl to power premier home theaters and multi-room audiophile systems with effortless musicality. Operating in high-bias Class A/AB mode, this flagship five-channel powerhouse delivers 250 watts continuous RMS into all five channels simultaneously across 8-ohm loads, scaling effortlessly to 400 watts per channel into 4 ohms. Built around an enormous 2.2 kVA encapsulated toroidal transformer and complementary JFET/MOSFET input stages, it produces thunderous dynamic slam, liquid midband warmth, and vanishingly low distortion across demanding speaker configurations.
Key Features & Innovations
Legendary John Curl Circuit Topology — the Parasound A51 Five Channel Power Amplifier utilizes direct-coupled architecture with complementary matched JFET input stages, MOSFET driver stages, and high-current bipolar output transistors, free of capacitors or inductors in the signal path.
High-Bias Class A/AB Operation with 60A Peak Current — operates in pure Class A at normal listening levels for lush, sweet tonality, smoothly transitioning to Class AB to deliver up to 60 amperes of peak current per channel for instantaneous dynamic bursts.
Massive 2.2 kVA Encapsulated Toroidal Transformer — incorporates an independent secondary winding for each channel alongside 164,000 µF of power supply filter capacitance, ensuring complete channel isolation and limitless transient reserve.
Balanced XLR and Unbalanced RCA Inputs with Gain Controls — features gold-plated balanced XLR and unbalanced RCA inputs for all five channels, each equipped with dedicated gain trim switches and individual ground-lift switches to eliminate system ground loops.
THX Ultra2 Certified Performance — meets the stringent reference standards established by Lucasfilm THX, guaranteeing studio-grade output levels, low-noise fidelity, and thermal stability in large dedicated screening rooms.
FAQ — Parasound A51
Can the Parasound A51 Five Channel Power Amplifier drive 4-ohm speakers on all channels?
Yes. The Parasound A51 Five Channel Power Amplifier is designed and unconditionally stable into low impedances, delivering a continuous 400 Watts RMS per channel across all 5 channels driven simultaneously into 4 Ohms.
Does this amplifier support automatic power triggering?
Yes, the A51 features multiple turn-on options including a 12V DC trigger input with loop-through, an adjustable audio signal-sensing auto-on circuit, and a heavy-duty front-panel manual power switch.
Can the A51 be rack mounted in custom AV equipment racks?
Yes, Parasound includes heavy-duty rack-mount adapter brackets and rear support rails, occupying 4 rack spaces (4U) in standard 19-inch equipment racks.
How does the Class A/AB bias operate during daily listening?
The amplifier is biased heavily into pure Class A for the first several watts, where the majority of delicate musical details and vocal textures reside, ensuring sweet, non-fatiguing sound without harsh crossover notch distortion.
Why Buy From Us
Authorized Parasound dealer offering 100% genuine factory-authentic Halo products with full manufacturer warranty protection
Experienced home theater and multi-channel audio specialists available to guide preamp pairing, gain staging, and power distribution
Dedicated post-purchase technical support for balanced interconnect setup, trigger wiring, and thermal ventilation planning
Insured freight delivery with heavy-duty reinforced dual-box packaging on every order
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Studio-grade balanced XLR analog interconnect cable bundles
