Усилители мощности моно — Lamm Industries M2.2

The M2.2 from Lamm Industries is a hybrid monoblock power amplifier that combines a solid-state input stage, a single 6922 triode tube in the second stage and a MOSFET output stage. It runs with no overall feedback and is sold in pairs, one chassis per channel. In 2006 the US list price was USD 21,090 per pair.

Key specs that matter

Rated output is 220 W RMS into 8 ohms and 440 W RMS into 4 ohms, with further ratings published for 2 ohm and 1 ohm loads, and the M2.2 can be configured through its rear bias switch to deliver up to 900 W into 1 ohm. The first 41 W into 8 ohms are delivered in pure class A, or 20.5 W into 4 ohms, after which the circuit moves into class AB up to full power. Lamm specifies a bandwidth of 4 Hz to 155 kHz at 0 to minus 3 dB, total harmonic distortion of 0.3 percent with 96 dB of noise separation measured from 22 Hz to 22 kHz. Input sensitivity is 1.076 V for full output into 8 ohms, and the input impedance is 41 kOhm. Each unit stands 210 mm tall, 432 mm wide and 495 mm deep and weighs 32.2 kg.

Engineering and use context

In this hybrid arrangement the tube sits where it handles voltage gain between two transistor stages, while high-speed MOSFET devices carry the current into the loudspeaker. A toggle on the rear panel selects between two load ranges, one for 1 to 6 ohm speakers and one for 8 to 16 ohm speakers, which changes how the output stage is biased and where the class A region ends. Both XLR and RCA input jacks are fitted, so the amplifier accepts balanced and unbalanced sources without an adapter. Every chassis carries a double set of five-way speaker terminals, which makes bi-wiring from a single monoblock possible. The weight comes largely from the power supply and heat sinks needed for a design that idles with a large share of class A current, so each unit needs open space around it for ventilation and a sturdy shelf or floor platform.

Pairing

Because the sensitivity is close to 1 V, almost any line-level preamplifier with a normal output can drive the M2.2 to full power. The impedance switch lets the owner match the amplifier to low or high impedance loudspeakers, and the ability to run into very low loads means difficult electrostatic or multi-driver designs remain within its operating range.

Alternatives

The Lamm ML2.2 offers a single-channel all-tube route from this New York company instead of the hybrid circuit.