Tube Power Amp Reviews

Neither its rather pedestrian name nor Manley Labs' own literaturehttp://www.manleylabs.com/containerpages/100200.html">literature; gives much of a clue as to the 175 monoblock's special pedigree. Where are the bands, the fanfare?! After all, the rolling-out of a 6L6–based high-power audiophile-grade tube amplifier definitely qualifies in my book as a momentous occasion. Deplorably, such happenings are rare indeed; the 6L6 has been unjustly neglected in high-end circles.

There's something special about big tube amplifiers. No other audio component has such a primal appeal or can so quickly reduce grown (?) audiophiles to Homer Simpsons sighing, "Mmmmm...toooobs." EveAnna Manley, president of Manley Laboratories, understands the effect of high-powered tubes on the audiophile brain and shares the obsession. A Harley rider, mountain climber, and devoted music lover, she is one of the industry's most individualistic characters. You just have to appreciate a gal who ends each CES by blaring Rage Against the Machine at top volume.

My reviews always begin in bizarre ways. Take David">http://www.stereophile.com/david_manley_tubes_logic_amp_audiophile_soun… Manley...please! (Just kidding.) On the last day of Winter CES 1995, I found myself towing a tuckered-out JA to a few final rooms. (This was just after the January '95 David Manley/Dick Olsher tube-rolling brouhaha, footnote 1, regarding who should do what to whom, and with which particular tube.) So as we passed Manley's room, John Atkinson thought to stick his head in (the noose) and say hello.

This should have been a recipe for disaster.

It's no secret. David Manley has not been big on single-ended amplifiers. Not enough muscle. You're better off with push-pull. Still, with a growing market for single-ended stuff, I'm sure Manley saw a need to do something. Of all tube designers, Manley has always been among the most prolific.

Prelude
The setting of the Prelude to our opera, The Margules Saga, is the California Audio Show, in August 2012. There, on first hearing Margules Audio's tube electronics, I wrote in my notebook, "great inner vitality, warm but with a welcome and appropriate bite." An encounter the following January inspired me to write, of a system that included an earlier version of the company's U280 amplifier, "The sound? Beautiful and warm. I've heard these electronics at two shows, and each time, I've left the room feeling good."

It began when I reviewed the MartinLogan Montis loudspeaker (September 2012). The amplifiers I had to drive the pair of them were the PrimaLuna ProLogue Premier integrated ($2999), the Audiopax Mk.II (no longer available; the Mk.III costs $22,000), and the Simaudio Moon Evolution W-7 ($9000). The first two are tubed, with power in the 30–40Wpc range; the solid-state Simaudio puts out 150Wpc. The Audiopax, which sounds great with my Avantgarde Uno Nanos, turned out to be not such a good match for the Montises: weak in dynamics, and too soft sounding. The PrimaLuna and the Simaudio were better overall, each with its strengths and weaknesses, though neither was ideal. I really liked the ProLogue Premier's tonal characteristics, and wondered what a higher-powered tube amp would sound like with the MartinLogans.

I wasn't raised a McIntosh lad. My dad used Fisher, Bogen, Leak, and Ampex tubed electronics—and, at one time, even home-built speakers—to keep the house filled with a steady, enriching flow of Mozart. He never owned a Mac component, and, when going upmarket, reached for B&O, alas. So while I knew that many audiophiles hold tubed McIntosh gear—especially the early designs—in very high regard, I was somehow never bitten or smitten. But let's face it—for lo these many years, McIntosh has been for many the name in quality American audio. Take my friend Dan, to whom I've referred several times in the pages of Stereophile. He runs a tubed Conrad-Johnson 9 preamplifier, but wouldn't dream of giving up his 270Wpc solid-state McIntosh MC7270. He's goldurn proud of it!