T + A has marked their 40th anniversary with stand out mono block power amplifiers... “The M 40 HV provides our HV-series High-Res players and pre-amplifiers with an extremely unique, uncompromising power amplifier which satisfies the most extreme audiophile demands under a vast range of operating conditions. Of course, it can also be used to form the perfect power amplifier for any other High-End set of equipment. One thing we have learned in our forty-year history is that the world of electro-acoustics does not permit a single perfect solution to all requirements; instead every overall design philosophy offers its own strengths and weaknesses. And that is why we have consistently developed optimum solutions for each requirement, whether it is based on valve technology or the very latest form of digital signal processing.”

The M 40 HV combines our experience in the various areas of High-End audio technology: audiophile valve construction for the input stages, High Voltage technology for the transistor stages, intelligent thermal processor control for the output stages together with our usual uncompromising case design and construction.

To achieve all this we have equipped our finest power amplifier with a circuit design which is unique in the world, combining classic analogue techniques, valve technology, High Voltage amplifier design and intelligent parameter control. The entire input amplification section is based on carefully selected High-End valves of the 6SN7 type, operating in Class-A mode. This results in a very harmonious sonic image, and instils the musical and tonal advantages of valve technology in the sound character of the M 40 HV. The input stage is designed as a symmetrical differential amplifier exploiting an all-valve cascode circuit. The subsequent voltage amplifier stage is a High Voltage (HV) J-FET amplifier circuit with triode performance characteristics, which also operates in pure Class-A mode. The result is excellent bandwidth and an agile performance which defines the sound qualities of the amplifier as a whole.

At the input side the current amplifier stages are based on MOSFET driver transistors whose performance curve harmonises superbly with the HV voltage amplifier stage. At the output side the current amplifiers are equipped with no fewer than twenty extremely high-performance ring emitter bi-polar transistors. These components satisfy the most extreme demands in terms of current supply capacity and bandwidth.

High Power Mode 
Nominal power 
into 8 Ohms
into 4 Ohms 550 Watts
1000 Watts
Peak power 
into 8 Ohms
into 4 Ohms 570 Watts
1070 Watts
High Current Mode 
Power up to 60 Watts pure Class A, up to 250 Watts Class AB
Frequency response + 0 / – 3 dB 1 Hz – 150 kHz
Slew rate 65 V/μs
Damping factor > 115
Signal / noise ratio > 114 dB
Distortion (5W, 4 Ohms, 1 kHz) < 0,009 %
Inputs unbalanced (RCA), balanced XLR 3 pin and XLR 4 pin
PWR supply capacity 180000 μF