Tube Power Amp Reviews

Even as the gulf narrows between the sounds of the best solid-state and the best tubed amplifiers, most listeners remain staunch members of one or the other camp. Similarly, when it comes to video displays, the plasma and liquid-crystal technologies each has its partisans, though that conflict's intensity is relatively mild, perhaps because video performance, unlike audio, is based on a mastering standard that establishes color temperature, gray-scale tracking, color points, and the like (I'm deeply in the plasma camp). But in audio, the "standard" is whatever monitoring loudspeaker and sonic balance the mastering engineer prefers, which makes somewhat questionable the pursuit of "sonic accuracy." Still, in a power amplifier, a relative lack of coloration is preferable to amps that Stereophile editor John Atkinson has characterized as "tone controls"—usually, if not exclusively, of the tubed variety.

After I read Brian Damkroger's rave review of the Audio Research Corporation's Reference 5 SE line stage in the November 2012 Stereophile, I was excited about getting the review sample into my system so that I could do a Follow-Up (February 2013). However, the sample had already been returned to the factory, so I called ARC to see if it could be rerouted eastward to me. Chief Listener Warren Gehl answered the phone.

"Sure, you can listen to the Ref 5 SE, but I'd assumed you were calling about the Reference 75 amplifier."

"Reference 75? What's that?"

"It's our newest amplifier—a half-power version of the Reference 150."

The challenge is biblical in character, if not in scope: A half year after railing, in these pages, against our industry's overabundance of products that cost more than $20,000, fate has given me such a thing to review.

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.

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.

Even at its humblest, a 300B is a fine thing. And at its best, this classic triode output tube can deliver some of the most intoxicating music playback imaginable. If tubes are liquor, the 300B is clearly absinthe. (The 2A3 is Cognac, the 45 is Armagnac, the F2a is Tequila, and the EL34 is vodka—which is to say, you can make almost anything out of an EL34, from the repulsive to the sublime.)

One drizzly, gray morning I found myself with an unexpected hole in my schedule and an unusual hankering for doughnuts. Since my move to Portland, Oregon, last August, people from around the country have told me that I just had to try the over-the-top creations over at Voodoo Doughnuts. So I donned my raincoat and walked through downtown Portland for one of Voodoo's fried, raised, and glazed treats. Once inside Voodoo's tiny storefront, I chose two confections: a maple-bacon bar (yep, they put a whole strip of bacon on top of a doughnut), and an Old Dirty Bastard doughnut with chocolate frosting, Oreos, and a peanut-butter topping. They were delicious, and way more doughnut than one man should eat.