Model L1 represents top of the line in LAMM hybrid and solid-state audio equipment. It is one of the best creations of its designer’s professional career–a result of years of intensive research directed at attaining the most accurate reproduction of recorded music. Unique topology and application of the most advanced technological resources and processes bring the L1 near the threshold of excellence in sound reproduction. A main distinction of the L1 from any other comparable type of preamplifiers is its almost inaudible sonic signature. When connected to an appropriate type of power amplifiers, and especially LAMM amplifiers, it assures the extraordinary transparency of perceived sound and recreation of a three-dimensional soundstage in the home, recording studio, etc., without boundaries and limitations.
The L1 features a topology that brings out the most natural sound performance in the audio path, as well as graceful and sophisticated design. Its unique circuitry utilizing specially selected superlinear high voltage MOS-FET transistors ensures a class A operation from input to output, with no overall feedback at any stage. All stages, including high current output buffers, are single-ended. A unique electronic protection circuit enables manual muting of the outputs until the preamplifier has stabilized after a turn-on; it also enables functioning of the preamplifier in a “muting” mode during operation and automatic switching to muting in case the AC line voltage drops or is interrupted. Other features include 5 inputs; 2 tape loops with tape-dubbing capability; output signal phase switch; balanced and single-ended outputs; and built-in remote on/off for LAMM power amplifiers.
Special care was taken in designing the power supply which utilizes a high voltage (+350V) high speed vacuum tube voltage regulator. Using this voltage regulator, in conjunction with other technical aspects, enables the reproduction of tiniest nuances and three-dimensional subtleties in the music palette (provided that such details had not been lost in a recording process). A somewhat unusual combination of high voltage vacuum tube power supply and superlinear high voltage MOS-FETs allows to attain an enormously large output swing while retaining practically constant harmonic contents of the signal with an absolute dominance of the second harmonic.
In designing the L1 special attention was directed toward optimization of the output impedance of the preamplifier with an aim of attaining practically full independence of the output impedance from frequency, as well as to allow the preamplifier to drive (without audible sonic degradation) significant capacitive loads created by many modern interconnect cables.
Each preamplifier is carefully hand-crafted with matched components of the highest quality, some of which include military graded low noise DALE metal film resistors; ALPS potentiometers; PRC wire wound resistors; ELECTROCUBE and ROEDERSTEIN film capacitors; high frequency switching grade CORNELL DUBILIER electrolytic capacitors; specially selected long life vacuum tubes; highest quality heavy duty gold-plated RCA jacks from ESOTERIC AUDIO; and gold-plated NEUTRIC XLR connectors. The L1 features a custom-designed power transformer. AC voltage is intensively filtered by special RFI power line filter.
Summing up the above, we take the liberty in stating that we have been able to create a preamplifier with practically no sonic signature, of course, taking into consideration the fundamental limitations inherent in reproduction of live music by electronic means.
The L1 works on all world AC line voltages without elaborate modification.
U.S. Patent D371,555.