Mono High Current MOSFET
Control Room Amplifier

M500 Mono High Current MOSFET Control Room Amplifier

As an alternative to its stereo sibling, the M500 monoblock has been designed to offer the ultimate in smooth extended bandwidth for the most advanced audiophile monitoring possible. Utilizing the same twelve 100 watt MOSFET output devices and high current power supply, a different approach to the front end design has yielded a slightly warmer, less aggressive presentation with an enhanced and truly astounding deep bass response. Also, in our attempt to emulate the "tube" sound, a significantly higher output impedance has been used to provide a damping factor that does not vary with frequency. In traditional designs the lower damping factor exhibited at the frequency extremes is remedied in a tube amplifier's circuit by the necessity of using an output transformer... with its unfortunate contribution of sonic impurities. In the M500 we have applied the benefits of this concept without the drawbacks, providing very strict cone motion control at all frequencies. Since the M500 is not a bridged version of the S400, but a dedicated parallel mono unit, it does not supply quite the output of an S400 bridged, but is, however, quite happy at all impedances down to one Ohm. In stereo pairs the M500 will bring out the best from the finest monitors, while single units are the perfect choice when mono subwoofers are added in the nearfield environment.


Absolute polarityNon-inverting
Input sensitivity.95 volts RMS
Input impedance balanced/unbalanced3.65K Ohms/51K Ohms
Output impedance.060 Ohms, 20Hz-20KHz
Damping factor135, 20Hz-20KHz
DC offset< 100 mV
Signal to noise105dB
Frequency response (3dB points)5Hz-160KHz
Total harmonic distortion.1%
Rise time (10% to 90% transition)900 nanoseconds
Slew rate60 volts per microsecond
Maximum peak current capability80 amperes
Power output (not including 3dB dynamic headroom)
        8 Ohms150 watts RMS
        4 Ohms275 watts RMS
        2 Ohms450 watts RMS
Dimensions18.9"W x 13.4" D x 3.5"H (2 rack spaces)
Shipping weight32 lbs.
Warranty3 years

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