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MONO MOSFET POWER AMPLIFIERS

Musical Technology’s M series MOSFET power amplifiers are the result of years of painstaking circuit design. The overriding goal in this process was to retain in a solid state amplifier the sweetness and warmth as well as the speed and definition typical of our FT hybrid amplifiers, amplifiers heralded by critics, musicians, and experienced audiophiles alike. To achieve absolute channel separation and a wider more clearly defined soundstage, these amplifiers are mono. Each amplifier, therefore, can be located near the speaker it is driving for better control and the virtual elimination of capacitive, inductive, and resistive reactance in the interface. Large heat sinks permit high bias or pure class A operation.

MOSFETs have long been praised for their desirable musical qualities; and due to intrinsic thermal stability and immunity to secondary breakdown, they require no protection or current limiting in the signal path. Fed by an oversized power supply the MA4 and M8 deliver the current necessary to effortlessly drive any kind of loudspeaker, from low impedance designs to the most demanding electrostatics. High damping factors ensure excellent control of LF speakers, and consequently rocksolid, yet articulate bass reproduction.

M Series MONO POWER AMPS

The driver circuit in each case is formed by two fully complementary cascode class A transistor stages, each with its own local feedback, yielding excellent linearity and extended bandwidth. The power stage is biased pure class A at normal listening levels (in the models M9, M14, M22). The MA4 and MA8 deliver 40 Watts, respectively 80 Watts in pure class A (2 Amperes bias current) and must not be confused with amplifiers on the market which claim to be class A, but which in reality fall greatly short of the mark. Pure class A biasing cancels crossover notch distortion and brings about improvements in both bandwidth and phase integrity, thus enhancing the quality and definition of the sound.

The M1020 is a class of its own. With 200 Watts into 8 Ohm, 400 Watts into 4 Ohm and 100 Watts in pure Class A mode, it has very little competition. With 12 MOSFETs and 60,000 µF buffer capacity, it can drive everything, and has no problem with electrostatic speakers or other complex loads.

Components have been carefully selected for their sonic performance

and reliability. In each case a handsome chassis of anodized brushed aluminium, first rate mechanical integrity, and massive black anodized heat sinks ensures reliability and steady performance, even after hundreds of hours of play.

The MA8 and M24 represent refreshingly musical design efforts. They render musical shadings and nuance with an honesty that must be heard to be appreciated. The two models are identical in circuit topology, differing only in power supply, bias, and features.

High Bias Am­pli­fiersM9M14M1020
Power Out­put 8 Ohms (nom­i­nal):>90W>140W>200W
Power Out­put 4 Ohms (nom­i­nal):>130W>220W>400W
Fre­quency re­sponse (-3 dB):5Hz – 150kHz5Hz – 150kHz5Hz – 150kHz
Sen­si­tiv­ity and input im­ped­ance1.0 V/100kOhm1.0 V/100kOhm1.0 V/100kOhm
Har­monic dis­tor­tion<0,1%<0,1%<0,1%
S/N Ratio>85 dB>85 dB>85 dB
Damp­ing fac­tor>80>130250
Out­put stage4 se­lected MOS­FETs

tor. trans­former, 250VA
6 se­lected MOS­FETs

tor. trans­former, 380VA
12 se­lected MOS­FETs

tor. trans­former, 380VA
Power sup­ply30,000 µFca­pac­i­tance30,000 µFca­pac­i­tance60,000 µFca­pac­i­tance
Di­men­sions23cm (W) x 9.5cm (H) x 33cm (D)23cm (W) x 9.5cm (H) x 33cm (D)32cm (W) x 9.5cm (H) x 33cm (D)
Weight:6.5 kg10 kg12 kg
Pure Class A Mono Am­pli­fiersMA4MA8
Power Out­put 8 Ohms (nom­i­nal):>40W>80W
Power Out­put 4 Ohms (nom­i­nal):>65W>135W
Fre­quency re­sponse (-3 dB):5 Hz – 150 kHz5 Hz – 150 kHz
Sen­si­tiv­ity and input im­ped­ance1.0 V/100kOhm1.0 V/100kOhm
Har­monic dis­tor­tion<0,1%<0,1%
S/N Ratio>85 dB>85 dB
Damp­ing fac­tor>130>250
Out­put stage4 se­lected MOS­FETs

tor. trans­former, 230VA
8 se­lected MOS­FETs

tor. trans­former, 300VA
Power sup­ply30,000 µFca­pac­i­tance88,000 µFca­pac­i­tance
Di­men­sions23cm (W) x 9.5cm (H) x 33cm (D)23cm (W) x 9.5cm (H) x 33cm (D)
Weight:6.5 kg6.5 kg