Fresh from the Bench: Benchmark AHB2 Stereo Power Amplifier

July 24 2015, 18:06

This in-depth review of the Benchmark AHB2 Stereo Power Amplifier, published in audioXpress April 2015, clearly explains why you should listen to this one. Benchmark’s new AHB2 stereo power amplifier uses feed-forward error-correction technology patented by THX that virtually eliminates crossover distortion. Designed in response to the needs of high-resolution audio sources, each channel of the AHB2 actually has two amplifiers — the main bi-polar Class-AB amplifier for driving the loudspeakers, and a low-power error-correction amplifier with ultra-low distortion levels. Gary Galo spent some time with it and explains all the reasons why he was impressed. Very impressed.

Benchmark Media Systems is a company that has successfully bridged the professional and audiophile worlds. It is an American firm that designs and manufacturers all its products at its Syracuse, NY, facility. The AHB2 was named after Allen H. Burdick, who founded Benchmark Media Systems back in 1983 and passed away in 2013. This is a fitting tribute, since the AHB2 continues the Burdick legacy of technical innovation. Indeed, Benchmark’s new power amplifier is arguably the most innovative product the company has produced to date. The AHB2 challenges several established “conventions” regarding power amplifier design including:

• The best audio power amplifiers are inefficient and generate lots of heat. High-efficiency invariably means inferior performance.

• Class-AB operation of the output stage is a minimum requirement for high-end sound, but Class A is preferred (generating the greatest amount of heat).

• High-end power amplifiers are large and heavy, with massive power transformers, heatsinks, and large power supply filter capacitors.

The power output rating of Benchmark’s new stereo power amplifier, belies its size and weight at 100W / channel into 8 Ω. The entire package measures 11” × 4” × 9.5” and weighs 12.5 lb. The AHB2, with both channels driven, can also deliver 190W / channel into 4 Ω, and 380 W into an 8-Ω operating bridged mono. Output current is rated at 18 A, per channel, both channels driven (protection shut-down circuitry kicks in above that threshold).

As Gary Galo writes: “The most immediately striking characteristic of this amplifier is a jaw-dropping level of detail and resolution. The AHB2 redefines the word “transparency” and will make many competing amplifiers sound veiled and foggy by comparison. The Benchmark amplifier lets you penetrate the densest orchestral scores with ease, never offering a hint of congestion. (I know I’ve written such things before, but the AHB2 takes it to a new level.)”

Click here to read the full review.

About the Author
Gary Galo retired in June 2014 after 38 years as an Audio Engineer at the Crane School of Music, SUNY, in Potsdam, NY. He now works as a volunteer, transferring vintage analog recordings in the Crane archive to digital format. He is the author of more than 280 articles and reviews on both musical and technical subjects. He is an active member of the Association for Recorded Sound Collections (ARSC) and has been a regular presenter at ARSC conferences. Several of his conference papers have been published in the ARSC Journal.
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