Усилители мощности моно — T+A M 40 HV

T+A released the M 40 HV mono power amplifier in 2018 as a product marking the 40th anniversary of the Herford company, and it belongs to the HV series. It is built to drive a single loudspeaker, which means two units per stereo setup. Its input section runs on valves, while the output side relies on bipolar transistors fed by a very large power supply, and the chassis stands upright rather than lying flat like the other HV units.

Key specs that matter

T+A rates nominal output at 550 W into 8 ohm and 1000 W into 4 ohm, with peak figures of 570 W and 1070 W respectively. A separate High Current Mode delivers up to 60 W in pure Class A or up to 250 W in Class AB. The response runs from 1 Hz to 150 kHz at +0/-3 dB, slew rate is 65 V/us, the damping factor is above 115 and noise sits more than 114 dB below full output. Distortion stays below 0.009 % measured at 5 W into 4 ohm at 1 kHz. The unit measures 56 cm high, 36 cm wide and 47 cm deep and weighs 52 kg.

Engineering and use context

The whole input amplification section uses selected 6SN7 valves working in Class A, arranged as a symmetrical differential amplifier with an all valve cascode circuit. The following voltage amplifier stage is a high voltage J-FET circuit with triode like characteristics, also in pure Class A. Two output stages each carry five pairs of bipolar transistors, twenty ring emitter devices in total. Capacitor banks total more than 180,000 uF, and each of the two transformers is rated at 1000 W. T+A describes the concept as a mix of classic analogue techniques, valve technology, high voltage amplifier design and intelligent parameter control. Mains operation is 110 to 150 V at 60 Hz or 220 to 230 V at 50 Hz with a rated draw of 1500 W, and standby consumption is under 0.5 W. The case comes in silver lacquer 47 or titanium lacquer 64, with the heat sink finished in black 42.

Pairing

Signal connections include an unbalanced RCA input plus balanced XLR inputs in both 3 pin and 4 pin form, and a trigger input accepting +5 to 20 V allows remote power switching from a preamplifier. Within the same HV range T+A offers the P 3100 HV preamplifier and the PSD 3100 HV preamplifier with streaming and DAC as front ends.

Alternatives

The T+A M 200 is a much smaller mono power amplifier from the Series 200 line, using Purifi Eigentakt Class D output stages for 210 W into 8 ohm and 420 W into 4 ohm in a 5 kg case.