LAMM L2.1 REFERENCE PREAMPLIFIER REVIEW IS COMING


Lamm  L2.1 Reference preamplifier is heading towards the Mono & Stereo headquarters. I'm really looking forward to explore the  L2.1 Reference that it represents Lamm Industries' top of the line hybrid (tube/solid-state) preamplifier. As Lamm M1.2 Reference is already my daily partner for evaluations and music enjoyment I'm quite excited about this arrival...  

DESIGN ELEMENTS

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.

The L2.1 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 super-linear 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 3 inputs; 1 tape loop; output signal phase switch; balanced and single-ended outputs; and built-in remote on/off for LAMM power amplifiers.

The L2.1 has a separate power supply that utilizes a choke contained filter, vacuum tube rectifier and voltage regulator.

COMPONENTS


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 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 L2.1 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; unique TKD stepped potentiometers (41 detents); PRC wire wound resistors; ELECTROCUBE and ROEDERSTEIN film capacitors; high frequency switching grade CORNELL DUBILIER electrolytic capacitors; specially selected long life vacuum tubes; high quality heavy duty gold-plated RCA connectors; and gold-plated NEUTRIC XLR connectors. The preamplifier power supply features a custom-designed super-low noise toroidal power transformer. AC voltage is 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 L2.1 works on all world AC line voltages (100/120/220/230/240V).