Parasound HCA-2205A

A five-channel amp that paired John Curl's circuit design with a 2.0 kVA transformer and 150,000 µF of filter capacitance, for under two grand.

Overview

Eighty-five pounds. That's the number a collector notices first when he gets a hand under a Parasound HCA-2205A. The amp is rated at 220 watts per channel into 8 ohms or 300 watts into 4 ohms, all five channels driven, 20 Hz to 20 kHz at 0.03% THD. It weighs 85 lbs (38.6 kg) because Parasound put a 2.0 kVA power transformer and 150,000 µF of filter capacitance inside the chassis. Parasound's own advertising leaned hard on that, billing the amp as a "foundation-shaking, hold-onto-your-chair, ultra-high-current" design with over 220 watts and 60 peak amps per channel, all with Home THX Ultra certification (Audio, October 1998, p.75). By the company's claim, it was the largest Home THX Ultra-certified amplifier available at the time.

The design work came from John Curl, one of the engineers Parasound leaned on most heavily during this era. The output stage runs high-bias Class-A/AB. The extra idling current pushes the output transistors deeper into Class A before they hand off to AB, which trims odd-order harmonics. Inside, forty beta-matched 15-ampere, 60-MHz bipolar transistors handle the output, J-FETs sit at the input, and MOSFETs drive the stage. Curl's rationale was that the FETs behave and sound more like tubes than ordinary solid-state devices. His words for it were clarity, warmth, and richness. Buy the tube comparison or not, it's a real design choice.

The chassis is a nicely styled, very well-built black box that looks like virtually every other five-channel amp in its class. No exotic cabinetry, no tropical wood side panels. The front panel carries indicators for power, standby/operate, current overload, and thermal overload. Around back you get Tiffany-style RCA input jacks and gold-plated five-way speaker binding posts, plus color-coded gold-plated brass banana plugs from the factory. There's audio and 12V DC triggering so an A/V preamp can wake the amp remotely. There are also gain controls on the rear panel, a curious inclusion that Audio (January 2000, p.90) noted with some puzzlement, since most A/V preamps handle level adjustment themselves. Dimensions are 19 inches wide, 7⅝ inches tall with feet, and 19½ inches deep.

On the bench, the HCA-2205A held up. Audio (January 2000, p.92) measured frequency response flatter than the companion AVC-2500 preamp's, plus zero, minus 0.08 dB on the worst channel, with channels matched within 0.05 dB. Noise was very low for an amp of this size. The 60 and 120 Hz hum peaks were visible but inaudible, and A-weighted noise measured −76.3 dBW in the worst channel and roughly −86 dBW in the others. Crosstalk stayed below −80 dB in all but one channel pair, and then only above 6.6 kHz. Distortion at 10 to 100 watts per channel was quite low even in the worst channel. The reviewer's summary was blunt: the amp performed very well in all respects, an impressive showing given the power on tap.

Listening impressions were consistent across the review. The HCA-2205A was exceptionally clean and transparent, with a touch more upper-midrange and treble energy than much of its competition, which read as apparent detail, dynamic energy, good imaging, and air. That tilt cuts both ways. Paired with speakers already hot in the upper mids and treble, it could get hard, and it reproduced bright or close-miked source material all too well. Bass was a genuine strength. The amp controlled low frequencies tightly and quickly, tighter by the reviewer's account than many subwoofers, though it struggled with some older Apogee and Infinity speakers whose impedances dip very low. The recommendation was to run it with good full-range speakers and no sub, or a sub that wouldn't mask what the amp was doing.

The sources don't agree on price. A pro-audio directory listing put the HCA-2205A at $1,999, while Audio's January 2000 review listed $2,495. Both figures are plausible for different points in the run or different distribution channels, so treat the price as somewhere in that range rather than a single fixed number. Either way, Audio (January 2000, p.92) called both the 2205A and its AVC-2500 stablemate very affordable high-end products, components that approached the performance of far more expensive equipment without the exotic price tag. The reviewer's verdict was that they were some of the best components around for buyers chasing high-end sound on a real-world budget.

Five channels of John Curl-designed, THX Ultra-certified Class-A/AB power for the price of a single high-end stereo amp is a lot of amplifier per dollar. The build quality, meaning that 85-pound chassis and the military-spec approach to the circuit, suggests it was meant to last. The rear-panel gain controls and 12V trigger make it easy to integrate into a modern or period surround system. The main cautions are the treble tilt and the low-impedance speaker limitation. Feed it easy loads and it will behave. Feed it Apogees and it may not. The weight alone means shipping is a real cost, so plan on local pickup or careful freight.

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