Усилители мощности стерео — TAD TAD-M2500MK2

The TAD-M2500MK2 is a two-channel power amplifier in the Evolution series of TAD Laboratories, the Japanese company whose name stands for Technical Audio Devices. Evolution is the entry line of the brand, positioned under the Reference components, and the MK2 version replaced the original M2500 in the same family. The UK price is GBP 24,000. Two cosmetic versions exist, one with a silver upper half over a black lower half and one finished completely in black.

Key specs that matter

Rated output is 250 W per channel into 8 ohms and 500 W into 4 ohms, with both channels driven from 20 Hz to 20 kHz at 1% THD. Distortion stays below 0.05% across the same band at 250 W into 4 ohms. Bandwidth reaches 5 Hz to 50 kHz at the 3 dB points and 10 Hz to 100 kHz within 1 dB. Noise sits 112 dB or more below output, measured to IHF with shorted input and A-weighting, while balanced gain is 29.5 dB. Sensitivity is 1.5 V balanced or 0.75 V unbalanced, and input impedance is 220 kilohm on XLR and 47 kilohm on RCA. The amplifier consumes 250 W in use and under 0.5 W on standby. It measures 440 x 170 x 467 mm and weighs 43 kg.

Engineering and use context

Class D circuitry is arranged in a fully balanced form, with each channel built as a bridged transformerless pair of amplifiers. Left and right are kept apart from input terminal to speaker output, and the supplies and transformers are divided both between the channels and between the positive and negative rails. The toroidal transformers are wound on grain-oriented steel, and TAD points to the tight coupling of primary and secondary windings as the reason for low conversion loss. Proprietary 33,000 uF electrolytic capacitors store the energy. The output transistors are leadless MOSFETs chosen for their very low on-resistance, and the efficiency of the Class D stage keeps heat low enough that no conventional heatsinks are needed. The enclosure is machined out of a 90 kg aluminium block, so the only joints are the connections themselves, which TAD says stabilises ground potential and gives high stiffness with high internal loss. A three-point cast-iron insulator base damps vibration.

Pairing

Full power into 4 ohm loads makes the M2500MK2 suitable for low impedance loudspeakers as well as 8 ohm designs. The high XLR input impedance means a balanced preamplifier sees an easy load, and mains versions are offered for 120 V 60 Hz in the United States and for 220 to 230 V 50/60 Hz in Europe and Asia.

Alternatives

The TAD-M700S is the two-channel Reference-series power amplifier from TAD, rated at 175 W per channel.