September 2002

LAMM Industries LP2 Phono Pre-Amplifier
Review by Dick Olsher
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  Eddie Gorodetsky and David Greenberger point out on their website When LPs Roamed the Earth that my generation can mark its age by the realization that one of its icons - John Lennon - died without ever having seen a compact disc. So in the midst of the digital age, I am definitely older, perhaps wiser, and to confess the truth, I still consider analog to be one of life's distinct pleasures.

For the past two years my phono system has evolved and crystallized to near perfection. Its foundation has been the Kuzma Stabi Reference turntable, outfitted with the Graham Engineering model 2.2 tonearm. Arm height is no longer a problem, as I've obtained an arm board from Franc Kuzma, machined with the proper thickness for the Graham. My main stay MC cartridge is still the Symphonic Line RG-8 Gold, hand-made by A. J. Van den Hul. Phono pre-amplifiers have been whittled down to a custom version of the Arthur Loesch circuit, hand-built by J.C. Morrison, and a single commercial unit - the Air Tight ATE-2. Over the years it has become clear to me that the necessary ingredients for an exceptional phono stage are threefold: tube circuitry, a high transconductance tube at the input, and a tube-based power supply.

The model LP2 delivers on all three counts. As with the Loesch circuit, the Western Electric 417A/5842 vacuum tube is used for voltage gain. A phono pre-amplifier is synonymous with high gain and low noise. The only way to get there with tubes is to use a high-transconductance triode, as triode noise decreases with increasing transconductance. Eric Barbour provides an excellent survey article on the WE 417A in issue #7 of Vacuum Tube Valley. This tube was designed and introduced into service by Western Electric in 1948 as a low-noise first stage for broadband RF pre-amplification. According to Barbour, its noise performance is world class - competitive with even modern MOSFETs. I concur with his assessment that the 417A is the premier tube to use in the first stage of phono or microphone pre-amplifiers. He laments the fact that almost nobody is using this tube in high-end pre-amplifiers today even though it's easy to find, while manufacturers rush to "slap, cheap, nasty Russian 6922s in expensive preamps." One caveat: as with other RF tubes, 417As should be pre-selected for low microphonics.

Enter Vladimir Lamm, progenitor of Lamm Industries, Inc., and one of the brightest stars shining in the tube design firmanent. When he described the design to me at the 2002 Winter CES, he pushed my buttons, and I mean ALL of my buttons. Even before I auditioned the unit, I was convinced that Vladimir really nailed this one. A pair of selected WE 417As is used per channel to provide the moving magnet (MM) stage's voltage gain. The nominal MM gain is 37.65dB, which is about right for use with an external line stage or control preamplifier. A low-output MC requires an additional 20 dB of gain. To keep the noise floor as low as possible, Lamm uses for this purpose a high-quality step-up (x10) transformer manufactured by Jensen Transformers. No output buffer stage is used, which accounts for the somewhat high output impedance of about 3.5KOhm. It is recommended that the LP2 be coupled with line-stages that have an input impedance of at least 40 KOhm.

The 417A likes it hot; hence it is run at a high plate current. The chassis feels quite warm to the touch and benefits from several inches of clearance for adequate ventilation. Some of the heat is generated by the power supply, which is based around a 6X4 full-wave rectifier tube. A substantial low-noise power transformer is used. In addition, the filter network is absolutely beefy: a double Pi-filter with two large chokes, and a capacitor reservoir of about 150 joules (in the deluxe version). The circuit topology features an accurate passive RIAA EQ network, and no open loop feedback. Separate inputs are provided for MM and MC cartridges, selectable from the back panel.

Each pre-amplifier is hand-crafted and extensively tested. All units are said to undergo a final 72-hour burn-in period and are then retested and re-measured. All measurement results are recorded in a production report maintained for each piece of gear. Exceptional passive parts are used throughout. Two versions of the LP2 are offered (standard and deluxe), and although I have only auditioned the deluxe version, I suspect that its bass performance is superior to that of the standard version. This is clearly a case of not gilding the lily. The deluxe version is further improved by the sort of design features that generally enhance bass performance: a larger capacitor reservoir in the power supply, polystyrene bypass capacitors for all film caps in the signal path, and better chassis damping. The deluxe version weighs in at some 40 pounds - more that some power amplifiers! The external design by Lamm's own admission is "elegant yet self-effacing," and fits in with their philosophy that "high-end audio equipment should be a means for contact with music, not an eye-catching piece of furniture." It is definitely that - a talisman for connecting with the music. And on a personal level, as a black Labrador dog lover, I find that the basic black finish suits me just fine.

The Sound

Using the MC inputs, I had no trouble accommodating the gain needs of my low-output cartridge. Vladimir is sure that the LP2 is one of the quietest phono preamplifiers on the market today, and all I can say is that this puppy is unbelievably quiet - especially considering its tube vintage. The music swells up from a velvety black background. Black velvet is the right metaphor here because there's no perceptible hash or grain to interfere with the retrieval of inner detail. Clarity of transients is greatly enhanced by the ability to follow the decay portion well below what would be considered a normal noise floor. Every additional dB of noise reduction translates directly into a "dB" of clarity. The LP2 was able to unearth nuances buried in the groove wall. It felt like a high-powered microscope, able to dig deeper into the foundation of the music than its competition. And it's all about detail. Emotions are in encoded into the music signal by means of low-level volume/microdynamic (tremolo), pitch (vibrato) modulations, and their associated time cues. To connect with the music's full emotional power, the full spectrum of encoded detail must be preserved through the amplification chain. It would be a cardinal sin for any phono stage to mask detail. The LP2 excelled in capturing the vibrancy and urgency of human voice, the sheen of string tone, and the interplay of massed voices.

Its overall presentation was immediate and direct, yet musical textures sounded naturally sweet and relaxed. Transient attack unfolded with great precision. Some phono stages appear to smear out the music's time base, dulling the leading edge. Not so with the LP2: speed of attack was very much in evidence. In the case of a piano, there's almost no sustain. Tones and chords are almost entirely attack and decay. With a good piano recording it is easy to separate the men from the boys. The LP2's phrasing was consistently superb in this regard. Very often speed, as in the case of solid-state amplification, is accompanied by mechanical sterility. The LP2 managed to combine speed with a refreshingly lucid and natural voicing.

The tonal balance is very much on the neutral side of reality. You'd be hard pressed initially to identify the LP2 as a tube circuit. It lacks the excesses of classic tube stages. There's no tube warmth, tube glare, syrupy midrange textures, overly liquid voicing, or muddled bass. The overall sound character tends to mirror that of the following links in the chain. The LP2 allows the sound of the following line stage and power amplifiers to clearly be heard. For example, tube rolling at the line stage was clearly audible. If you're inclined (like me) to slightly romanticize the sound, you'll have to nudge the tonal character in that direction later on in the chain.

Another of the WE 417A's virtues is dynamic expressiveness. Not surprisingly, the LP2 displayed tremendous headroom. It was never at a loss in scaling the macrodynamic scale from soft to very loud. And it did all that with no perceptible change in the distortion spectrum. Some preamplifiers tend to sound brighter and more harsh as they're pushed harder. Not a problem at all with the LP2, which remains sweet sounding and composed under all signal drive conditions. It was also outstanding in bringing to life microdynamic nuances, but fell a little short of the magical standard set by the Loesch phono stage. Note, however, that the Loesch is quite a bit noisier, and so sacrifices a bit of detail for dynamic animation.

The LP2 was capable of painting a breathtaking soundstage. Image focus was precise, but even more thrilling was its ability to properly portray the ebb and flow of image outlines. The head movements of a vocalist in front of a microphone, the apparent expansion of the image size with volume, and the depth perspective of each instrument were resolved with laser precision.

Reproduction of the bass range was superb. The definition and impact of bass lines was never better - tailor-made for acoustic bass. If you're into jazz, you'll appreciate the rock solid foundation the LP2 provides. There was a time, when my standard of describing tube gear's bass was to narrow the context and state that the level of performance was very good for a tube amplifier or preamplifier. No such apologies are necessary in the case of the LP2.

Conclusion

I've lived with some of the best and most expensive phono preamplifiers currently in production. The Convergent Audio Technology and Jadis immediately come to mind. Let me make this perfectly clear: the LP2 exceeds the standards set by its competitors, regardless of price or prestige. It is a unique product that blends together some of the traditional solid-state strengths of solid stage designs such as bass power and low-noise, with the glorious harmonic textures and dynamic conviction of tubes. The Lamm Industries LP2 makes a statement, and it's clearly about the sonic potential of the WE 417A. This tube in the right setting has the potential to exert a powerful magnetic pull on musical detail and microdynamics, bringing low-level detail and emotions to the forefront. The LP2 is that right setting: it harnesses the 417A's total musical power. To my mind, it is easily the most important achievement in phono stage artistry of the last decade.

Specifications

All the measurements were taken with the 41kohm load connected to the pre-amplifier's output 

Rated Output Voltage
F = 1 KHz:
MM input to output 0.125 Volts RMS
MC input to output 0.125 Volts RMS

Voltage Gain
F = 1 KHz:
MM input to output 75.5 ± 2% or 37.65 ± 0.2dB
MC input to output 750 ± 2% or 57. 5 ± 0.2dB

RIAA Accuracy
from 20Hz to 20kHz: better than + 0.0dB/-0.5dB

Total Harmonic Distortion from 20Hz-20KHz; RIAA de-emphasis: no more than 0.1%

IM Distortion (60Hz:7KHz 4:1) SMPTE; RIAA de-emphasis: no more than 0.1%

Inputs: Gold plated RCA

Signal-To-Noise: Better than 83dB

Price: $6,290; deluxe version $6,690

Company Information

Lamm Industries Inc.
2621 East 24th Street
Brooklyn, NY 11235

Voice: (718) 368-0181
Fax: (718) 368-0140
Website: www.lammindustries.com
Email: lamm.industries@verizon.net