Solid State Power Amp Reviews

What is it about a component that makes the blasé High Ender sit up and say, "Hey, this is special!"? What elements of its reproduction reach out to you and won't let go? How does the intrepid audio reviewer find a way to describe these hopefully recurring moments of musical discovery which define the high-end experience? How many times, after all, can you say, "Ooooo, ahhhhh, that's the best [insert some part of the frequency range here]," ad nauseam? How much difference is there, anyway? Therein lies the tale...

Our Lamm experience began auspiciously enough. The door buzzed. I opened it to find two smiling individuals—one of average height, the other tall and gangly. The tall one looked like a bona-fide bomb thrower to me. Molotov cocktail, anyone? The hallway was chockablock with two large wooden crates. I looked at the guys expectantly. "Hah-lo, I am Vladimir One...thees, Vladimir Two," the average-height one said gesturing to his tallish companion. I put my head out the door and glanced left and right to see if any KGB were about. Seeing none, I bade them enter; after suitable introductions, we set about installing the amplifiers.

Vladimir One turned out to be the Principal Lamm, V. Shushurin. I'd first heard the Lamm 1.1s when they were presented at the 1993 Summer CES under the Madison Fielding marque, and was among many impressed by the sound they were making driving a pair of Wilson WATTs/Puppies. The Lamm Model 1.1 is essentially the same amp as the Madison Fielding, but is now presented by its designer rather than by a third party.

I somehow appreciate Vladimir's very Russian way of looking at things. He believes we listen to music not only with our ears, but with our entire bodies. "The body reacts to sound in some kind of emotional way," he explained, "producing involvement on many different levels." He looked at me suspiciously at this point, and told me that "Sometimes, when I'm trying to explain this, people think I'm a little crazy!" I reminded him that I'm the guy who writes about Shun Mook. He reminded me that he used to play percussion in a symphony orchestra! I guess we're even!

In Vladspeak, then: "Due to its direct contact with the environment, the body is able to perceive the finest of vibrations—or musical information, so to speak." He went to great pains to explain that the human "hearing mechanism" is far from perfect—especially from the standpoint of high-end audio requirements. Vladimir is not uninformed on the issue: he's done extensive research and mathematical modeling of how we hear. That's why he believes that those electronics engineers who try to create equipment with perfectly flat and ideal parameters are doomed to failure.

This in spite of having been, in a past life, an engineer in the military industry, designing electronic equipment for the space program. "You know, rockets and missiles!" Subsequently, he became the chief designer of a large audio company in Russia. When I told him I had no idea there even was such a beast, he told me, "You didn't lose anything not knowing about this company!" He's designed a roomful of high-end audio equipment, including amps and preamps—many of them tubed—even a turntable. His ultimate system in Russia had single-ended tubed midrange and tweeter amplifiers, with push/pull on the bottom end.

So, the measurement/best-sound paradox was difficult for him. "If the amps measure as they should from my point of view, it creates a sound with soul. You find musical ecstasy from sound, not measurements. Therefore, although my amps may have acceptable if not perfect measurements, they do conform to the criteria of my design." For instance, there's no negative feedback in his amps, because "Our hearing mechanism doesn't know anything about feedback." Good point, Vladimir.

Look for the Model M2.1, a 200W hybrid monoblock for those who feel they need more power; the Model DM1, a 125Wpc class-A/AB all-MOSFET stereo amp (no tubes, somewhat less costly); and the Model L1 line-stage preamp, which uses tubes (as voltage regulators) and has an overall MOSFET topology.

A tree grows in Brooklyn
The M1.1 is neither overly large nor too petite; rather, it's...well-proportioned—properly sized for function. They run hot, as any design with a class-A output stage will do, but not too hot. They are hefty, but, at 64.5 lbs each, aren't excessively so. The M1.1s are conservatively rated at 100W into 8 and 4 ohms in pure class-A. Maximum output into either load hovers near the 140W mark. The amps will pop 200W into 2 ohms, and 300 big ones into 1 ohm. The generously illustrated, very complete, and technical manual calmly states, "The M1.1 is capable of driving impedances below 1 ohm." I believe it.

On the rear panel of the amp is a Load Selector switch, which is meant to be set to the corresponding impedance of the speakers they're to be used with, with an LED signaling the choice (1–6 ohms or 6–8 ohms). This switch was set for 1–6 ohms throughout the test period. (My Avalon Ascents have a relatively benign impedance averaging 6 ohms.) The load switch changes the bias of both the idle current and the supply voltage to deliver 100W into both 8 and 4 ohms. For instance, 8 ohms/100W class-A requires an idle current of 2.5 amps; 4 ohms/100W requires 3.5 amps. The M1.1 begins doubling power from 4 ohms down. According to Vladimir One, the M1.1s will drive "any load that you can imagine. If this is your job and you have enough money, you can buy these amps and use them as a welding machine!" Of course.

Each Lamm M1.1 has a hefty grounding terminal on the rear panel—one feature of what Vladimir has dubbed the "Groundlift" system. Lifted, "the circuitry floats above the Earth, and the chassis is connected to the Earth wire (third pin on mains plug), which ensures the intended shielding function of the metal chassis." I should report that at no time did either of the monoblock Lamms "float" above the Michael Green Amp Stands. This in spite of heroic attempts to achieve this blissful state—ie, quaffing mass quantities of 20-year-old Russian Cognac. They shivered a little, but never floated.

The M1.1 is configured with both SE and XLR balanced inputs (pin 2 hot). RCA connectors are wired in parallel with pin 2; therefore, only one of these inputs should be connected. If your preamp inverts polarity, the M1.1 is ready for you. It comes with an additional RCA jack for phase-inverted inputs, and a shorting plug to stuff into the unused non-inverting jack. (The shorting plug should not be used if the balanced input is employed.) As the CAT SL-1 Signature is exclusively single-ended and non–phase-inverting, that's the input I employed throughout the test period.

Each monoblock is built around high-quality parts. Eight separate power supplies run from two 850VA Plitron-sourced toroid power transformers. The M1.1 is a hybrid design, sporting a military-grade 6922 tube in the second amplification stage, and 12 high-voltage, high-speed MOSFET output devices. An oversimplification of the circuitry might read something like this: The input is a cascode differential long-tail pair with a Wilson Current Mirror. (Leave me alone—I don't know what the hell that means!) The second stage exploits and "ignites"(footnote 1) the 6922 in single-ended mode. (Vladimir believes that this second stage of tube amplification largely accounts for the sound of his amplifier.) The third stage is a single-ended high-current buffer that drives the MOSFET outputs. (Power MOSFETs have a large input capacitance which needs to be charged using a high-current driver stage.)

Here are some specs, so that the pocket-protector brigade can see if these amps might be suited to their systems. Rated output voltage (continuous sinewaves, 20Hz–20kHz) is 40V peak into 8 ohms (corresponding to 200W peak) with 5A peak current under the same conditions. Input impedance is 41k ohms shunted by 470pF of capacitance. Output impedance is typically 0.2 ohms. Typical power consumption is 300W at rated output at 8 or 4 ohms, and at idle.

A flashing red lamp marks the action of the soft-start circuitry, activated at turn-on until the amps are stabilized. After a "suitable time delay, you will hear the click of the engaged speaker relay," and the lamps cease their winking. The protection circuitry came on in the right channel only once—when I inexplicably elected to clean the stylus of the Symphonic Line RG-8 with the gain up. I heard the amp latch into its standby mode, and, after a "suitable delay," was again with music. This security of operation built confidence in the Lamm's seemingly bulletproof design.

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Footnote 1: A Japanese tubed-electronics manufacturer called Mary Anne, Inc. charmingly advertises in Glass Audio that "Every driver tubes of Euphony Series are ignited in DC." That's so sweet...