Solid State Power Amp Reviews

When I first saw Anthem Statement's M1 at the 2011 CEDIA Expo, it was a bolt from the blue. Happening on this flat, black slab of an amplifier lying on a display table or bolted to a wall, reminded me of the appearance of the iconic monolith in Stanley Kubrick and Arthur C. Clarke's 2001: A Space Odyssey. The M1's dimensional ratios are not 1²:2²:3², and there are many other one-rack-unit amps—yet, like the monolith on the moon, the M1 was in such striking contrast to everything else in its environment that it demanded attention and reflection.

"Grand Integra" is the name Onkyo has given to its line of perfectionist-oriented audio products, and the M-508 is the cheaper of Onkyo's two Grand Integra power amplifiers. (The flagship model is the $4200 M-510, reviewed by Larry Greenhill in Vol.8 No.8, featuring "high current capability," and rated at 300W continuous per channel.)

A recent (unpublished) letter to the editor argued that the reference for audio perfection is the sound of real instruments in a real space. The writer claimed that, since the art and/or science of audio is advancing, and because it is a "scientific truth" that the closer you get to perfection, the less divergence there is components, that therefore there should be less difference in sound among the components listed in Class A of Stereophile's "Recommended Components" than among those in Class B, much less Class C. This should be true of loudspeakers, he said, but even more true of top-rated amplifiers, since "they inherently have less divergence."

As large as a small file cabinet and weighing 223 lbs, MBL's most powerful amplifier, the Reference 9011, is a tour de force of electronics design and implementation that will set you back $53,000 if you're a single-ended stereo enthusiast, or $120,000 if you like pure balanced mono.

To judge from the $6400 Mimesis 8, Goldmund walks its own way when it comes to power amplifier design. High-end solid-state amplifiers from US companies like Krell, Mark Levinson, Threshold, and the Jeff Rowland Design Group marry massive power supplies to large numbers of output devices (these often heavily biased to run in class-A), built on chassis of such nonmagnetic materials as aluminum. By contrast, the Mimesis 8 has a magnetic (steel) chassis, and uses a relatively modest power supply, that for each channel based on two main 4700µF reservoir capacitors. The 8 offers just two pairs per channel of complementary output MOSFETs (Hitachi K134/J49). These carry a modest bias current of around 80mA total.

"That's just silly on so many counts, Antony."

I was talking last winter to Musical Fidelity's Antony Michaelson, who had been enthusing about his forthcoming stereo amplifier, the AMS100. It would be physically enormous—almost a yard deep—and commensurately heavy at 220 lbs. Despite its bulk, its maximum rated output would be just 100Wpc into 8 ohms. It would also be expensive, at $19,999. And to cock a snoot at environmentalists and their concerns, the AMS100's output stage would be biased into class-A up to its rated 8 ohm power, meaning that, even when not playing music, it will draw around 10 amps from a typical US wall supply of 120V. This also means that it will run very hot, making the amplifier impracticable for summer use in homes without central air-conditioning. Like mine.

Cycles can be seen in the fortunes of companies. Likewise cycles can be seen in the performance of companies' products. A particular range will appear to have got it just right, whatever "it" is. The designer may have hit a winning streak and thus steal a lead over the competition. C-J set a new state-of-the-art preamp standard in the late '80s with their Premier Seven, and some of that expertise and experience are beginning to pay off in the shape of new high-performance preamplifiers at realistic prices. Moreover, the pressure was on to develop better power amplifiers to match. Two important products have emerged from all this in C-J's moderately priced FET range, namely the PF-1 preamplifier and the matching MF-200 power amp. By audiophile standards, these are moderately priced at $1295 and $1995, respectively.