Model L2.1 Reference is an evolvement of its predecessor -- the acclaimed L2 Reference -- and represents top of the line in LAMM hybrid and solid-state audio equipment. Unique topology and application of the most advanced technological resources and processes bring the L2.1 near the threshold of excellence in sound reproduction.
As the original L2 circuitry was virtually flawless, it was the emergence of new active electronic components that opened up a possibility of transforming the L2.1 circuitry into a vehicle which brings the sound reproduction level even closer to the sound of live music than before.
A main distinction of the L2.1 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.
In designing the L2.1 special attention was directed toward optimization of the output impedance of the preamplifier with an aim of attaining nearly 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.
Special care was taken in designing 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 super-linear 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.
The L2.1 Reference employs a pure class A operation from input to output, with no overall feedback at any stage; all stages, including high current output buffers, are single-ended. Also featured are specially selected high voltage super linear MOS-FETs in the signal path and TKD stepped potentiometers for volume control – the best available on today’s market.
The preamplifier’s audibly neutral power supply features a choke contained filter, a full-wave vacuum tube rectifier and vacuum tube voltage regulator which allow to virtually eliminate the hum and buzz and, ultimately, to ensure the authenticity of the essence of sound throughout the entire dynamic range without any coloration.
A unique electronic protection circuit enables 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 3 inputs; one tape/home theater processor loop; output signal phase switch; balanced and single-ended outputs; protection circuitry designed to enable manual muting of the output signal; and built-in remote on/off for Lamm power amplifiers.
In a nutshell, the L2.1 Reference includes the following upgrades and modifications as compared to the L2 Reference:
Each preamplifier is carefully crafted with the finest materials and top quality parts like military-grade DALE/VISHAY metal-film resistors, RCD wire-wound resistors, TKD 41-step volume control potentiometers of the highest quality available on today’s market, BOURNS multi-turn potentiometers, VISHAY electrolytic capacitors, ELECTROCUBE, EPCOS and RIFA/KEMET film capacitors; HAMMOND chokes, god-plated NEUTRIC connectors, and military-grade low-noise long-life vacuum tubes. The L2.1 Reference features a custom-designed super-low noise power transformer.
AC voltage is filtered
by special RFI power line filter.
- increased immunity to unwanted radio frequency interferences propagated via both radiation and conduction over signal lines & AC power systems
- certain modifications in protection and time delay circuitries
- improved signal/noise ratio
- replacement of a number of critical components with newly available types of better quality [in particular, replacement of electrolytic capacitors in the tube voltage regulation section with newly developed high density polypropylene capacitors of comparable size and value(!)]
- utilization of a technologically new type of pc-boards of superior quality, with gold-plated traces and thru-holes.
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.