Lamm Industries M2.1 monoblock power amplifier
The world of audio is analogous to the world of sports. With a few notable exceptions, the correlation between measured excellence and sonic distinction has been, at best, loose. The ultimate test, that which separates the great from the merely good, is the listening room. It's there, where the line between a thing done well and a thing done ill is infinitesimally thin, that a component's intangibles determine whether it falls short or ascends to the heights.
For nearly a decade, Vladimir Lamm has dedicated himself to creating audio equipment that meets his own demanding standards. Lamm's journey has not been easy; born and educated in the former Soviet Union, he homebrewed audio gear while working as a research scientist and, later, as the director of a factory that made consumer electronics. High-quality home audio equipment simply did not exist in the USSR, but since emigrating to the US, Lamm has more than made up for lost time—every piece of his equipment reviewed by Stereophile has landed in Class A of "Recommended Components." Were Lamm not the modest man he is, he could stake a strong claim to being the most honored and awarded audio designer of the last 10 years.
Lamm is a dedicated man of science—his equipment is built to mathematical and electrical models, not just to a preconceived notion of what music should sound like. Given his relentlessly objective methodology, it is all the more striking that every piece of Lamm gear that I have heard has what Jonathan Scull described in his review of Lamm's tubed M1.1 power amplifier back in the April 1995 Stereophile (Vol.18 No.4): an intangible that can only be called soul.
Lamm Industries is probably the only company in the High End whose amplifiers' prices are in inverse relationship to their power output. At $16,490/pair, the M2.1 monoblock amplifier is the company's least expensive (a relative term when dealing with Lamm components) and most powerful (footnote 1). The M2.1 is a hybrid design, and an unusual one. The amp's input stage is solid-state, with video buffers used for each signal phase driving a differential pair of JFETs, but then a "specially selected" military-grade 6922 (6DJ8) tube drives the six pairs of complementary MOSFET power transistors.
The M2.1 is specified to produce 200W into 4 or 8 ohms, and will tolerate loads as low as 1 ohm, which indicates a very stoutly engineered power supply. "While most class-AB amplifiers have [an] idle current ranging from a few tens to a few hundred milliamps," states Lamm's website, "the M2.1's idle current is 1.4 amps at 8 ohms and 2 amps at 4 ohms and below." A rear-panel locking switch changes the output stage bias and voltage rails to allow the M2.1 run in class-A up to 36W into 8 or 4 ohms. It runs in class-AB from that level up to the rated power limit.
Vladimir Lamm is a serious man who presents his products in an appropriately serious way, right down to the massive wooden crates in which the M2.1s were shipped and their superb, clearly written owner's manual. The latter includes a most comprehensive set of measurements and specifications, with graphs and documentation galore.
The M2.1's appearance is pure Louis Kahn: form follows function (footnote 2) There are no fripperies or fancy accoutrements; what you see—a largish, well-proportioned black box covered with heatsinks—is what you get. The front panel is featureless save for a red power LED, the engraved Lamm logo, and two beefy handles. The money is spent inside.
Popping the top shows the M2.1's interior to be immaculately built and well-organized, with one lonely-looking 6922 tube standing in the center of the large double-sided circuit board, with plated-through holes. (Vladimir has a horror of dry solder joints; the M2.1's components are soldered on both sides of the board.) A massive toroidal transformer lives under the circuit board, potted and isolated so that it contacts neither the transformer cover nor the amplifier's chassis, thus minimizing mechanical noise. As is Lamm's usual practice, that circuit board is filled with the finest parts: Dale metal-film resistors, PRC wire-wound resistors, Electrocube and Roederstein film capacitors, high-frequency switching-grade Cornell Dubilier capacitors, Bourns multiturn potentiometers, and other spendy goodies.
On the rear panel, heavy-duty gold-plated binding posts and gold-plated Neutrik XLR connectors permit balanced connections, with Esoteric Audio RCA jacks. Also featured on the rear are two additions I wish more manufacturers would provide: a second set of handles to make moving the amp much easier, and separate single-ended input jacks for standard and phase-inverting preamplifiers (footnote 3).
Footnote 1: The M2.1's sibling, the 100Wpc pure class-A M1.1, costs $17,290/pair; the 90Wpc ML1.1 push-pull triode monoblock costs $22,690/pair; and the 18Wpc ML2, a single-ended-triode design, goes for a whopping $29,290/pair.—Paul Bolin
Footnote 2: According to reader Allen Edelstein (firstname.lastname@example.org), it was not Lou Kahn who first said that "form follows function" but Frank Lloyd Wright. "For Kahn, form was more like mathematical topology where a donut and tea cup are topologically equivalent. Shape was the personification of the more abstract form," clarified Mr. Edelstein.—John Atkinson
Footnote 3: Owners of Conrad-Johnson amps, among others, will find this last feature a blessing.—Paul Bolin