Parasound A51 Five Channel Power Amplifier Reviewed

Published On: December 28, 2008
Last Updated on: October 31, 2020
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Parasound A51 Five Channel Power Amplifier Reviewed

Parasound are masters of high-performance, high-value amplifiers. Andrew Robinson tries out the A51 five channel power amplifier and found the amplifier to live up to the company's reputation.

Parasound A51 Five Channel Power Amplifier Reviewed

  • Andrew Robinson began his career as an art director in entertainment advertising in 2003, after graduating from Art Center College of Design. In 2006, he became a creative director at Crew Creative Advertising, and oversaw the agency's Television Division, where he worked for clients such as TNT, TBS, History, FX, and Bravo to name a few. He now has one of the most popular AV-related channels on YouTube.

Parasound_A51.gifWhen it comes to high-performance, high-value power amplifiers, few do it better than Parasound. The A51, which is part of Parasound's Halo line of cost-no-object products designed in tandem with audio legend John Curl, has benchmark levels of performance, yet costs a reasonable $4,500. Cost no object, huh? If every manufacturer built sub-$5,000 cost-no-object products, the audiophile landscape would be vastly different.

Additional Resources
• Read more about Parasound Products here on
• Check out multi-channel amp reviews from Emotiva, Classé, Krell, Sunfire, Elan, Audio Research, Mark Levinson and many others.

The A51 is a THX Ultra2-certified, five-channel amp churning out 250 watts per channel into eight ohms and 400 watts per channel into four ohms. The A51 is a high-bias Class A/AB operating amp in a direct-coupled design with no capacitors or inductors in the signal path, powered by a massive toroid transformer. The A51 uses a MOSFET driver stage complemented by a JFET input stage. The A51 features both balanced and unbalanced input connections, as well as 24-karat gold five-way binding posts. It features large heat sinks along both the right and left sides, as well as down the center of the rear panel, separating the inputs from the binding posts to dissipate some of that class A heat. The A51 has a 12-volt trigger, as well as a detachable power cord, and comes standard with rack-mounting equipment, which is almost unheard of with an amp costing as little as the A51.

Getting beyond its inner workings, one cannot overlook the visual statement the A51 makes in your rack. With its smooth silver casework and slightly curved façade, the A51 is nothing short of gorgeous and mates beautifully with the rest of the Halo line of products from Parasound.

Read The High Points, The Low Points and the Conclusion on Page 2 


High Points
• With 250 watts on tap, the Parasound A51 will power virtually anything you can throw at it and probably more, making it ideal for robust high-performance home theaters and/or multi-channel audio systems.

• The A51 has a rhythmically soulful sound with a tremendously rich and natural midrange. The upper frequencies are detailed and lush without being harsh or fatiguing, though they lack that last ounce of air and extension that costlier amps bring to the table.
• The A51's bass is well-defined and extremely textured and robust, though it's no Krell and will not plunge to never-before-heard depths. However, for a sub-5K amp, the A51 is among the best all-round performers you're bound to find.
• Dynamically and in terms of spaciousness, the A51 is amazing, doing equal justice to both music and movies. 
• The A51's inputs and binding posts make cable management a breeze and keep your rack nice and tidy.

Low Points
• Because of its class A/AB design, the A51 does get a bit warm and should be installed in a properly ventilated space and/or rack. 
• The A51 is large and heavy, though not as bad as some, and is best moved and/or positioned by two people.

With a sub-$5,000 asking price, the Parasound A51 is a tremendous amplifier. While its asking price is far from cost no object, its performance is on par with the best, mating a beautiful midrange and non-fatiguing top end to a lively and punchy bass section that, while not the deepest-plunging, is one of the most musical I've encountered in a long while. With reputation and reliability in tow, the Parasound A51 is a stunner in almost every regard.

  • greg
    2009-01-23 06:12:37

    <p>Parasound I have respected for some time. But, it was not until I heard their amplifiers at HE 2007 did I understand what all the fuss is about. Tight, well defined bottom end. An excellent highs, not harsh at all. We need more of this type of product in the high end, and then maybe the crowds we are looking to grow this business will come out as we all hope one day.</p>

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