Solid power for surround sound

Parasound's Halo A 52+ power amp can drive a full complement of five home theater speakers with authority. This multi-channel powerhouse delivers 180 watts per channel with all five channels driven, and it's stable at low impedances, so it's compatible with a wide range of speakers. It offers three power-up options: manual, signal-sensing, and 12-volt trigger. And it was designed to exacting specifications by Parasound's in-house audio guru John Curl.

Class A/AB operation for smoother sound

The A 52+ uses a Class A/AB power circuit. You don't see an amplifier described that way every day, so let's break down the benefits.

Engineers and audiophiles generally agree that Class A designs offer the purest sound, but they tend to run hot and take up a lot of space. As a result, home audio amplifiers often use a compromise known as Class AB, which hands off part of the audio signal to a different set of output transistors at high power levels. AB can sacrifice a bit of signal purity, but it lets the amp run cooler and more efficiently.

So this Class A/AB amp operates in pure Class A mode up to a higher power level than most other amplifiers in its price category, before the second set of transistors kick in. The result is a sound that's smoother, less fatiguing, and more natural.

The legacy of John Curl

The A 52+ features circuitry designed by John Curl, a legend in audio engineering. He started his career in the 1970s, designing tape and video recorders at Ampex, and he had a hand in building the Grateful Dead's famous Wall of Sound. Curl has worked with Parasound since 1989, designing all of their high-power amplifiers and more. The power supply, transistors, capacitors and other parts in the A 52+ were chosen to offer high performance at a reasonable price.

Product highlights:

• 180 watts per channel into 8 ohms (20-20,000 Hz) at 0.05% THD with 5 channels driven

• 255 watts x 5 into 4 ohms

• designed by legendary audio engineer John Curl

• high-bias Class A/AB amplifier design

• large toroidal transformer

• frequency response: 5-100,000 Hz (-3dB)

• signal-to-noise ratio: 112 dB

• handles very low impedances for use with virtually any speakers

• five balanced XLR and five unbalanced RCA inputs

• heavy-duty gold-plated 5-way speaker terminals

• switchable turn-on options: manual, signal sensing, or 12-volt trigger

• detachable power cord

• rack mountable with the optional HRA 3kit