I've been tweaking my weekend multichannel system for years, but with my city system I've kinda faked it. I now realize that I listen more actively to the weekend system, and not only because that's when I have the time for it—the sound of that system is simply more engaging and psychologically immersive. So, with the growth of my library of SACD and DVD-Audio recordings to almost half the size of my CD collection, I told my wife that it was time to transform of "our" city stereo rig into a full-blown multichannel system.
Good things come in threes, they say. Well, three-channel power amps suit me just fine. My main component rack is at the back of the room, so I split power duties between a two-channel amp under the rack to drive my rear-channel B&W 804S speakers and, way at the front, either three monoblocks or a three-channel amp for the front three B&W 802Ds. I do this to ensure that the timbre of the front three channels is consistent. The outstanding performance of the Simaudio Moon W-8 dual-mono power amp (Stereophile, March 2006) almost tempted me to go with a stereo amp and a monoblock, but voicing and balancing a multichannel system with equanimity makes me want as much simplicity as possible. I guess manufacturers and users see it the same way; many new three-channel amps are coming on the market.
I've been enthusiastically tracking the development of Bel Canto's class-D amplifiers, from their original TriPath-based models to their more recent designs based on Bang & Olufsen's ICEpower modules. With each step, Bel Canto has improved their amps' sound quality and reliability.
The first time I ever heard stereo sound, it was in a shop on Manhattan's Radio Row. In addition to the Studer staggered-head tape deck, the system consisted of pairs of McIntosh C8 preamps, MC60 power amps, and monster Bozak B-310 speakers. I can still picture the room and almost hear the sound. I was then an impecunious high-schooler, and while I always strived to buy the best equipment I could afford, I unfortunately was never able to own any of these iconic products. However, when I saw McIntosh's new MC303 three-channel power amp glowing brightly on silent display at the 2008 CEDIA Expo, a light bulb went on over my head: I'd been assessing a series of three-channel and monoblock amps, and the MC303 would fit nicely into my New York City system.
As I write this, in early August, the global economy is in flux and the stock market gyrates, seeming in stark contrast with the gleaming, luxurious audio components that surround me. Perhaps there is some prescience in my rising interest in reasonably priced, high-performance products, as exemplified by the Oppo Digital BDP-95 universal Blu-ray player, which I reviewed in this column in September. Surely there must be other products that provide truly excellent sound at prices strikingly lower than expected.
How much amplifier power do you need? Most audiophiles figure a maximum of a few hundred watts per channel—beyond that, you're wasting your money or showing off. Others think that anything more than a few watts will mess up an amplifier's musical coherence or "purity," so they stop there and find uncommonly sensitive speakers, usually compression horns with cone woofers.
Musical Fidelity's "Supercharger" concept is simple, which is perhaps why no one had thought of it before: If you love the sound of your low-powered amplifier but your speakers are insensitive, or you just need more loudness, you insert the high-power Supercharger amplifier between your low-powered amp and speakers. The Supercharger loads the small amplifier with an easy-to-drive 50 ohms, and, in theory, has so little sonic signature itself that it passes on the sonic signature of the small amp unchanged, but louder.
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 enormousalmost a yard deepand 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.
Not every audiophile needs an amplifier powerful enough to tax a small town's power grid while simultaneously draining his or her bank account. So, having quickly sold out of its ultra-limited-edition, extravagantly powered and priced combo of kWp preamplifier ($14,995) and kW power amp ($27,995) that I reviewed in January 2004, Musical Fidelity (footnote 1) set about capitalizing on the enthusiastic reviews earned by those giants with less expensive, less powerful, "real-world" replacements.
Nothing like scarcity to create demand, right? Well, there's been a scarcity of Nuvistors out there for decades, and hardly any demand. Do you know about the Nuvistor, aka the 6CW4? It was a tiny triode tube smaller than your average phono cartridge. Enclosing its vacuum in metal rather than glass, the Nuvistor was designed as a long-lived, highly linear device with low heat, low microphony, and low noise---all of which it needed to have any hope of competing in the brave new solid-state world emerging when RCA introduced it in the 1960s.
Musical Fidelity's founder, Antony Michaelson, arrived at my house to help me set up the two chassis of his sleek, limited-edition, $30,000 Titan power amplifier. (The task requires at least two people.) A week later, a representative of Musical Fidelity's US importer, KEF America, dropped by to listen and to deliver three of Musical Fidelity's new V-series products: a phono preamp, a DAC, and a headphone amp. All three fit comfortably into a small paper bag; the price of the three was $700.
Thoughts of power, domination, and audio road-rage enter one's mind when contemplating Musical Fidelity's SUV-like, limited-edition, 20th-anniversary offerings (footnote 1). (Only 75 sets of kWPs and kWs will be made.) The gleaming, brushed-aluminum, two-box, oversized, overweight Tri-Vista kWP preamp is fortress-like—the "kWP" looks as if chiseled into the faceplate by grimy, sweaty hands. Each of its boxes weighs almost 56 lbs. The unit's milled-aluminum remote control, the size of a Volkswagen Microbus and looking like something Fred Flintstone might wield, must weigh over 5 lbs. The kWP outputs more juice than many power amps: 55V, with 20 amps of peak-peak instantaneous current!
The story of New Acoustic Dimensions, aka NAD, begins in the late 1970s. The company was founded as a dealer distribution collective to design and market reasonably priced serious high-end gear to cost-constrained audiophiles. By eliminating needless features and focusing manufacturing in low-cost production facilities, NAD has successfully delivered audiophile-quality gear for 20 years at prices little more expensive than mass-market department-store schlock.
A decade ago, many predicted that amplifiers with switching or class-D1 output stages would come to dominate high-end audio. In a postPeak Oil world in which the price of energy would always continue to rise, a class-D amplifier's very high efficiency in converting AC from the wall outlet into speaker-driving power would be a killer benefit. Although a conventional push-pull class-B amplifier has a theoretical efficiency of 78.5%, which would seem usefully high, this efficiency is obtained only at the onset of clipping; the need for the output devices to carry a standing bias current reduces that efficiency considerably, typically to around 50%. Class-A amplifiers are even less efficient, with a maximum of 25%; ie, three times as much power is dissipated by the amplifier as waste heat as is used to drive the loudspeaker (see "Sam's Space" in this issue).
"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.)