Lamm M1.2 Reference Monoblock Amplifiers - Class A Tube and MOSFET Hybrid

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General:
The Lamm M1.2 is a unique amplifier utilizing class A technology combined with a tube driven solid state output stage. MSRP for the pair when originally released was a hefty $17,290!

These amps sounded wonderful in our testing and are running strong at their rated output power. Perfect for someone who wants to try out a class A amplifier design. 

This particular pair has the benefit of new tubes, plus the DC offset and bias were adjusted on both amplifiers for maximum performance.

Along with the amplifiers will be their original crates for safe transport, plus a printed copy of the Operating Manual on heavyweight paper.

SkyFi Cosmetic Notes:
Very minor blemishes are present on the front of both amps. One amp has a tiny nick on the top surface of the face, the other amp has a small scratch on one of the handles. Cosmetic condition is excellent overall.

SkyFi Technical Notes:
The switches on the back require a slight outward pull before they can be operated.

Tube Notes: 
Both amplifiers are now fitted with strong, balanced, 6N30P Russian 6922 equivalent tubes.

Shipping:
These monoblocks packed in their original wood transit crates will ship via truck freight anywhere within the lower 48 US States for a flat $500. This figure includes full insurance. This freight charge will be automatically added during your checkout.

We can safely pack and palletize these amps to ship worldwide, just contact us for a quote. Local pickup welcome and we can also arrange a local courier depending on distance. Please contact us for details. This item is exempt from any Free Shipping promotions.

More from Lamm:
A milestone In high-end amplification

The M1.2 Reference monoblock power amplifier represents a top of the line product in LAMM hybrid and solid-state audio equipment. It is the pinnacle of its designer’s professional career and a result of years of intensive research directed solely at attaining the most accurate reproduction of recorded music. Unique topology and application of the most advanced technological resources and processes bring the M1.2 Reference to a threshold of excellence in sound reproduction.

Design Elements
A distinctive feature of the M1.2 Reference is its presentation of the extraordinary transparency of perceived sound which in turn assures the recreation of a three dimensional soundstage in the home, recording studio, etc. without boundaries and limitations. The M1.2 Reference is a masterful blend of design and engineering simplicity. It is a pure class A amplifier featuring high-speed MOS-FET transistors in the output stage with no overall feedback and special switch-selectable bias/voltage settings for 8- or 4-Ohm operation.

The bias setting switch assures the pure class A operation of the M1.2 Reference when matched with a speaker load of either 4 or 8 Ohms, whereas conventional class A designs double the power into 4 Ohms resulting in one fourth of the doubled power in class A and the rest in class AB (learn more about this in FAQ section of our website at lammdev.wpengine.com/faq/switch.html).

The M1.2 Reference is a hybrid design with one specially selected 6922 vacuum triode in the second stage.The M1.2 Reference is conservatively rated to deliver 110 Watts into 8 and 4 Ohms in pure class A operation (high and low impedance settings, respectively); 220 Watts into 2 Ohms, and 400 Watts into 1 Ohm (low impedance setting), continuous. The M1.2 Reference can drive any known speaker. The harmonic structure remains intact regardless of the speaker load, while the extreme clarity is maintained at all power levels.

Components
Each amplifier is carefully constructed and hand-crafted with the finest materials and parts currently available, some of which include military graded low noise DALE metal film resistors; PRC wire wound resistors; ELECTROCUBE and ROEDERSTEIN film capacitors; high frequency switching grade CORNELL DUBILIER electrolytic capacitors; BOURNS multi-turn potentiometers; HAMMOND filter chokes; military graded low noise long life vacuum tubes; high quality heavy duty gold-plated binding posts and RCA jacks; gold-plated NEUTRIC XLR connectors, and CAMAC-type coaxial connectors from FISCHER.

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 that 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 M1.2 _Reference_ works on all world AC line voltages. U.S. Patent No. D368,261; U.S. Patent No. 5,470,795; other patents pending.

Drives to any known speaker
The harmonic structure remains intact regardless of the speaker load, while the extreme clarity is maintained at all power levels.

Ultra low-noise power transformer
Custom-made toroidal power transformer has no mechanical contact with either the transformer cover or the chassis, assuring the absolutely unique clarity and micro-resolution during sound reproduction.

Transformer hum reducer
Special circuit reduces power transformer core saturation and residual mechanical hum.

Bias setting (load) switch
Switch-selectable biasing circuit maintains pure Class A operation of the output stage for all load conditions between 4-16 Ohms.

Ownership:
Single Owner

Connections:
RCA, XLR, IEC Power, Speaker Binding Post

General Sound:
Big beautiful musical sound with little fatigue.

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.

Included:
Monoblocks, Wood Crates, plus a printed copy of the Operating Manual on heavyweight paper. 

Packing:
Original Manufacturers Packing

Original MSRP:
$17,290.00

Specs:
Amplifier Operation & Output Power:
- Pure Class A operation
- No overall feedback
- 110W per channel (continuous into 8/4 ohms, pure Class A)
- 400W per channel (continuous into 2 ohms)
- 600W per channel (continuous into 1 ohm)
- Bias/Voltage Settings:
- Switch-selectable for 8- or 4-ohm operation

Tube & Transistor Configuration:
- 1 specially selected 6922/ECC88 vacuum triode tube per channel
- 12 high-speed MOS-FET output transistors

Power Supply:
- Custom-made 850-VA toroidal power transformer
- "Soft-start" circuit & vacuum tube rectifiers
- Protects components from large in-rush currents at power-on

Performance Specs:
- Frequency response: 4 Hz – 155,000 Hz

Power Compatibility:
- Operates on all world AC line voltages

Sound Quality Focus:
- Designed for exceptional clarity and micro-resolution during sound reproduction

Dimensions - Each Monoblock:
8.25" (21cm) Width 17" (43.2cm) Depth 19.5" (49.5cm)

Weight - Each Monoblock:
68.5 lbs.

Approximate Age:
2003

Link to Review:
Click Here

Link to Operating Manual:
Click Here

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

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

Testing Process:
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 a modern Amplitrex AT-1000 Professional 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 1 KHz test signal, slowly increasing 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 1 KHz square wave check and a 20 Hz to 20 KHz 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 minimum.

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.