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 3040Wpc 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!
The McIntosh MC 275 power amplifier has been born yet again. It's the Count Dracula of power amps. It refuses to stay dead. Introduced in 1961, the Mac 275, in its original hardwired edition, was produced until 1970. This was the amp I desired while in college but couldn't afford. I remember the Mac 275 fondly—rather like girlfriends from my college years.
It's been a while since I've had a classic amplifier in my system, and McIntosh Laboratory's MC275 is as classic as they come. Introduced in 1961 as the "powerhouse" of that era's newfangled stereo tube amps (two 75W amplifiers in one chassis!), the MC275 retained its position as the amplifier to ownchallenged only, perhaps, by Marantz and a few othersuntil 1970, when it fell prey to the widespread wisdom that transistors were king and tubes were dead, and the model was discontinued. The MC275 briefly returned in 1993, in a limited "Commemorative" edition to honor the late Gordon Gow, longtime president and chief designer of McIntosh Labs. To everyone's surprise, that edition sold well, and McIntosh, gingerly at first, crept back into the tube business.
Some audiophiles tend to get a mite sniffy around those of us who have expensive tastes and limited budgets. I've always been willing to spend the price of a new car on a set of speakers, but I never had the cash or credit. The sonic virtues of hefty, high-powered Krells and wondrous, single-ended tube designs always enchanted me, but when you're raising a family you make do. Through my experiences in a high-end audio establishment I learned the metaphysics of mixing and matching as befits my lowly caste, and I gradually developed sophisticated reference points, so that as the years swept by I managed to inch my way up the aural food chain.
In his "Manufacturer's Comment" in response to my review of the original Music Reference RM-200 power amplifier in the April 2002 issue, designer Roger Modjeski admitted that being a manufacturer was not his first choice. "Frankly, I'd rather consult than produce," he claimed. "I'd rather be making a living doing stand-up comedy," I said to myself after reading his comment.
Reviewing a vacuum-tube power amplifier is like having your pants pulled down in front of a large crowd of people. I don't know how else to describe the feeling of spending a month or two luxuriating in fabulous sound, then writing a glowing review, then receiving a copy of the review as it will appear in the magazine, complete with John Atkinson's assessment of the amp's test-bench performance, which is usually miserable.
Do you believe in beginner's luck? If so, some of your personality traits should be quite predictable. Let's see. You're very likely an optimist with a "bull-market" mentality, play the lottery, and, most important, bought a CD player within a year of its introduction, or a solid-state amp in the '60s. You're apt to mail in a profusion of bingo cards (you know, the kind Stereo Review is full of) and spend hours perusing specifications in the hope of finding a kernel of truth in all of that chaff. You'd particularly be appalled at that fellow I ran into the other day, who had bought an AR-1 in 1956 and waited another decade before buying another speakerjust to make sure stereo wasn't a fad. Hey, relax, I won't turn you in; the mere fact that you're reading Stereophile is sufficient reason for redemption.
Nagra's VPA amplification system consists of two slim, handsome monoblock amplifiers intended for vertical placement. They look good adjacent to the speakers. However, two 845 tubes put out a lot of heat, so the amplifier should be at least a foot away from your speakers...unless you're looking for a nice crackle finish.
I dig tube amps. When all's said and done, good tube amps seem to sound more like real life than most solid-state gear; even after listening to and enjoying the hell out of musical solid-state designs like the Audio Research D-240 II and the Muse Model One Hundred, once I hook up the big VTL Deluxe 225s again it's just like going home. I could go on about timbral accuracy and clearer midrange textures, but the bottom line is, music just plain sounds better when you shoot it through good tubes, and once most people experience that magic, they're hooked.
Ever since I became a Stereophile contributing editor, people have asked me, "How do you determine what equipment you're going to review? Do you get to pick your own, or does John Atkinson tell you what to do?"
I've chosen roughly 85% of the components I've reviewed for Stereophile, those choices made on the bases of what I find interesting, and what I think readers would like to know about. It's as simple as that.
The road to hell is paved with good inventions: clever ideas that appear, in hindsight, motivated more by a desire to sell clever ideas than to make musically superior products.
The DiaLogue tube amplifiers from PrimaLuna have, at their heart, a clever idea of their own: an output circuit that is user-switchable between triode operation, in which the screen grid of a tetrode or pentode power tube is defeated by means of connection to the tube's anode; and Ultralinear operation, in which the screen grid of a tetrode or pentode carries a portion of the AC music signal, supplied by a tap on the output-transformer primary, in a feedback-like effort to reduce distortion and increase power. Fans of the former often report a sweeter, more tubey sound, while fans of the latter report a tighter, more detailed, more timbrally neutral sound. Audio enthusiasts are given to reporting any number of things.
Everybody loves a bargain. No—make that: Most people love a bargain. Some just want the best, and they don't care about the cost. Some even distrust and reject out of hand any product that's not expensive enough. If you're one of these people, you might as well stop reading this review right now—the PrimaLuna ProLogue Three and ProLogue Seven are not for you. $1395 for a tube preamp? $2695 for a pair of 70Wpc tube monoblocks equipped with four KT88 tubes each? Must be based on old designs in the public domain using cheap parts carelessly assembled...