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Lamm ML2.1 Monoblock Tube Amplifiers, Factory Serviced - Stereophile Class A

Sale price£11,716.00
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Pickup available at SkyFi 479

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Lamm Ml2.1 Monoblock Tube Amplifiers Factory Service - Stereophile Class A Amplifier

Lamm ML2.1 Monoblock Tube Amplifiers, Factory Serviced - Stereophile Class A

SkyFi 479

Pickup available, usually ready in 24 hours

479 South Broad Street
Glen Rock NJ 07452
United States


This listing is for a $30k glorious set of tube amplifiers, recently serviced by the factory where they receded a full new tube complement and clean bill of health.

These will ship to you via freight on their original crates and complete like the they day they left the factory. Please note these amps are exempt from any free shipping promotions we may be running.

Cosmetically near perfect. 

More from Lamm:
ML2.1 is the direct replacement of the ML2 — the first in a line of LAMM single-ended amplifiers with a regulated power supply that represented a new generation of power amplifiers employing unique high current low impedance power vacuum tube triodes (6C33C) in both the output stage and voltage regulator.

Implementation of these triodes has allowed to create an output transformer with a very low turns ratio and, as a consequence, extended (as compared even to the most advanced modern vacuum tube amplifiers) frequency decade factor, as well as dramatically reduced leakage inductance.

The ML2.1 features the following upgrades and modifications as compared to the ML2:

  • Addition of a more user-friendly mains fuse holder.
  • Power transformer upgraded to accommodate the 230V mains operation (in addition to the already existing 100/120/220/240V in the ML2)
  • Modified output transformer
  • Addition of two handles on the rear to make it easier to handle the amps and protect the rear panel connectors during transportation
  • Heavy-duty speaker binding posts
  • Utilization of a much higher quality pc-board, and parts and materials that have become available in recent years

Chosen by the Design and Engineering Committee as one of the most innovative products of the year in the “specialty audio” category, the ML2 was a first single-ended amplifier on the market capable of reproducing a full range of audio frequencies and recreating the original spectral balance and harmonic structure of the recorded material with almost 100% accuracy. Another unique aspect of the design enables the ML2.1 to recreate a three-dimensional soundstage without boundaries and limitations while maintaining the extraordinary transparency of perceived sound.

A custom-designed output transformer, along with a unique output stage and high-current regulated power supply, allow the ML2.1 to drive most of the real world speakers and yield tremendous sonic stability under most dynamic conditions. Although the ML2.1s can drive most speakers, their full potential is realized in tandem with high efficiency speakers (94 dB and higher).

Two multi-turn trimming potentiometers accessible through special openings in the amplifier’s chassis, along with two sets of test points, allow the user to adjust and measure the nominal value of plate voltage and plate current of the output tube by using an external voltmeter.

In conceiving and executing an overall design of the ML2, the goal was to utilize the modern technology and processes while recreating a look reminiscent of the long-gone genuine vacuum tube era. Each amplifier is carefully constructed and handcrafted of the finest materials and world class parts, some of which include military graded low noise DALE metal film resistors; ELECTROCUBE and ROEDERSTEIN film capacitors; high frequency switching grade CORNELL DUBILIER and UNITED CHEMI-CON electrolytic capacitors; HAMMOND chokes; gold-plated NEUTRIC XLR connectors; and military graded low noise long life vacuum tubes.

Special attention was given to designing the toroidal power transformer, which has no mechanical contact with either the transformer cover or the chassis, and is suspended in a special encapsulant which almost completely absorbs even the residual mechanical vibrations. This plays a significant role in assuring the absolutely unique clarity and micro-resolution during sound reproduction.

The ML2.1 works on all world AC line voltages.

Single Owner

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab and listening room.

Everything like when it arrived new

Original Manufacturers Packing

Click Here

Original MSRP:

Tubed, monoblock power amplifier. Tube complement: one each 12AX7, 6N6P, 6AK5, 5651; two 6C33-B. Output power: 18Wpc into 4, 8, or 16 ohms at up to 3% THD (dBW). Input impedance: 41k ohms in parallel with 470pF. Input sensitivity: 775mV for maximum output. Frequency response: 20Hz-20kHz, -0.3dB, 3.0% THD.

Dimensions - EACH
16" W by 9" H by 20" D

Weight - EACH
70 lbs.

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Bes

Kimber Kable - Speaker Cables - Better

Kimber Summit Series Monocle XL Speaker Cables (PAIR) - Best

Kimber Summit Series BiFocal XL Bi-Wire Speaker Cables (PAIR) - Best If Applicable 

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

The SkyFi Testing Process for Tube Amplifiers:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect resistors and other passive components for signs of overheating. If tube arcing has occurred in the past we can usually spot discoloration on the output tube sockets. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a full test of all of the tubes. We use an Amplitrex AT-1000 Tube Tester which is capable of testing both emission and Gm with a high degree of accuracy. We document the results of each tube and replace any weak or suspect tubes before proceeding. When we power on tube amplifiers for the first time we usually use a variac and current limited AC supply and slowly raise the voltage up to nominal mains level while monitoring plate, screen, filament, and negative bias supply voltages where applicable. If everything is in order we feed a low level test signal into the amplifier’s input and monitor its output on an oscilloscope across an 8 ohm dummy load. At this point we are just looking to verify basic function and confirm that the output transformers are not damaged. Once we have verified that the amplifier is safe to operate, we connected it to full mains power. For fixed bias amps we set the bias to manufacturer spec. For cathode biased amps we monitor the plate to cathode voltage to determine if the output tubes are operating in a safe range. Once the output section is verified we move onto bench evaluation.

We start by feeding the input of the amplifier with a low level 1KHz test signal, slowly increase its amplitude while monitoring the amplifier’s output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping. At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. We finish off the bench evaluation with a 1KHz square wave check and a 20Hz to 20KHz sine sweep to assess the amplifier’s frequency response characteristics. This battery of tests will usually reveal if the amplifier has any issues that need further attention.

Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.

If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours. For tube amps we like to run this test at least twice. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when it has fully come up to temperature. We find this step to be essential, especially for vintage units.

SKU: 105079
Lamm Ml2.1 Monoblock Tube Amplifiers Factory Service - Stereophile Class A Amplifier
Lamm ML2.1 Monoblock Tube Amplifiers, Factory Serviced - Stereophile Class A Sale price£11,716.00