Tube Power Amp Reviews

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.

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 own—challenged only, perhaps, by Marantz and a few others—until 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.

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.

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 speaker—just 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.

The great debate that has long separated audiophiles is tubes vs solid-state. Other topics, CD for example, may temporarily steal the spotlight, but year-in and year-out no other subject is the cause of as much controversy as whether tubed or solid-state circuitry produces the more accurate sound. As is typical with long-standing feuds, the split runs deep, and tempers often flare.