Single-ended triode amplifiers (SETs) have a considerable following, but even their most devoted fans admit that its maximum power output is not among an SET's strengths. You'd be lucky to get an SET that puts out 7Wpc, and some (like those using the 45 tube) are closer to 2Wpc. Highly sensitive speakers (eg, horns) will tend to offset the power limitation, and SETs usually sound more powerful than their measurements indicate, but the laws of physics still apply: 2W is 2W, regardless of the kind of amplifier that produces it, and an amplifier's manner of clipping and recovery from overload take us only part of the way toward achieving greater volume.
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 vodkawhich is to say, you can make almost anything out of an EL34, from the repulsive to the sublime.)
Anyone over 40 who's worked in a hi-fi or record store will remember the Pfanstiehl catalog, a pulpy thing that most shopkeepers chained to their counters, like a phone book. Pfanstiehl made replacement styli for virtually every record-playing device of the day, and their catalog contained page after page of tiny line drawings of nothing but phonograph needles, all lovingly rendered in three-quarter view. You couldn't browse it without being brought up short: My God, how many different needles are there? And how is it possible that a single company could tool up for so many products and still make a profit?
"The only tubes that I want to see in my household are...the picture tube in my TV and the magnetron in the microwave oven," a Glendale, CA, reader recently wrote, and I guess his feelings reflect those of many when confronted by a supposedly "obsolete" audio technology. Forty years after the invention of the transistor and 20 after the widespread introduction of solid-state amplifiers (footnote 1), it must come as a shock to readers of the mass-market "slicks" that not only do a number of American manufacturers manufacture amplifiers and preamplifiers using tubes, but some of those companies—Counterpoint and Audio Research in particular—are among the more successful. It is the Classic 60 power amplifier from Minnesota-based Audio Research that is the subject of this month's lead-off equipment review.
The Audio Research D-160B has been heavily modified since the D-160A, and uses the same technology as the D-70, D-115, and D-250. It embodies William Z. Johnson's latest transformer and power supply designs, his latest choice of capacitors and resistors, and the same independent regulation of screens, drivers, and front end. D-160s and D-160As can be converted to D-160Bs for $1500.
The D-250 is the flagship of Audio Research's power amplifier range and, at 250 watts per channel, is the most powerful all-tube stereo amplifier currently available in the US. Under the circumstances, then, it is not surprising that it should also be one of the heaviest and largest.
They say you never forget your first time. For me, it was an Audio Research SP-6B that had been heavily modified by Analogique in NYC—which meant, among other things, that yellow capacitors shunted other yellow capacitors all the way up to the top plate. That first taste of the High End—prior to that, you might say my face had been pressed against the window—was definitely love at first listen. That SP-6B was warm yet detailed, and I ended up building a system around it that at least one friend described as a huge musical wet kiss.
When I attend Stereophile's annual Home Entertainment show, I rarely sit and listen to music for very long. Instead, I try to hit every room, press the flesh, find out about new products, and play a little jazz.
It's always good to have a reference. No matter the endeavor, references help guide us and set standards for all we do. For many hours of every day, I'm lucky to enjoy the reference of live, unamplified music. Right now, I average over 20 hours a week of rehearsals and performances of various ensembles, and four to five hours of listening to recorded music on my hi-fi. Clearly, for me, my musical reference is not the sound of my audio system, but the sound of live music created in various venues and acoustics.
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 amplifiera half-power version of the Reference 150."
For those who frequent the audio discussion groups on the Internet, the method by which Stereophile selects products for review seems to be a continuing source of fascination and conjecture. Supporters of fledgling manufacturers—whose products these Webcrawlers just happen to own—rail against the rule that products to be reviewed in the magazine must have at least five US dealers. Some suggest that Stereophile's selection of review products is all about catering to advertisers and friends in the industry, a process that seems intended to exclude their favorite products from consideration.
The VTM200 is the first Audio Research power amplifier I've reviewed. It took me 13 years, and ultimately I'm glad I'd put that much mileage on my reviewing odometer before tackling what turned out to be a most difficult assignment.
Ah, Brazil...land of coffee, the samba, Pelé, Rio-by-the-sea-o, and tube amplifiers. All right, so perhaps the amplifier connection isn't quite as well-established. But one Brazilian amplifier designer, Eduardo de Lima, has published articles in Glass Audio magazine that are viewed by many as groundbreaking, and his evolving products have been seen at various specialist tube equipment shows. De Lima—president, founder, product designer, and principal owner of Audiopax Sistemas Eletroacusticos—is an electrical engineer who started out designing equipment for a telecommunications company, but since 1995 he's devoted his talents to designing a wide range of audio products, including speakers as well as preamps and power amps.
Victor Tiscareno and Byron Collett of AudioPrism are known in audiophile circles for their complete line of power-conditioning products. (See Barry Willis' omnibus review in the December 1998 Stereophile.) Their intimate knowledge of the ever-capricious electrical supply has resulted in a series of front-end components bearing the company's logo. The flagship Mana Reference monoblocks, under consideration here, represent AudioPrism's collected wisdom and engineering savvy taken to its logical extreme.