BRAND: McIntosh

TYPE: Power Amplifier

One-of-a-Kind Solution for Bi-amping Loudspeakers


  • The MC901 Dual Mono Amplifier is truly a one-of-a-kind monoblock
    amplifier designed as the ultimate solution for bi-amping loudspeakers.
  • What makes the MC901 so unique is that it’s two amplifiers combined
    into one. Adding to the uniqueness is that each amplifier is of differing
    designs: the MC901 consists of a 300 Watt vacuum tube amplifier
    attached to a 600 Watt solid state amplifier on one unified chassis.
  • The 300 Watt vacuum tube portion powers the mid and upper drivers;
    the 600 Watt solid state section drives the power hungry woofers.
  • The full power is available to almost any speaker regardless if it has 2, 4
    or 8 Ohm impedance via our Unity Coupled Circuit output transformer in
    the vacuum tube section or our AutoformerTM in the solid state section.
  • Each amplifier section has its own discrete power supply so neither
    siphons power or performance away from the other.
  • Internal, adjustable crossover allows you to optimize the performance of
    both amplifier sections to your listening preferences.
  • Features our new DualViewTM Power Output Meter that independently
    displays the real time power reading of each amplifier section.
  • Power Guard® helps prevent distortion and clipping in the solid state section. New Power Guard Screen Grid SensorTM (SGS) helps prevent
    premature vacuum tube failure by monitoring the screen grid current in
    the KT88 output vacuum tubes. If the current becomes too high,
    Power Guard SGSTM dynamically attenuates the input signal in real time
    to keep the vacuum tubes operating at safe levels.
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Power Output:
Solid State section:
600 Watts into 2, 4 or 8 Ohms
Vacuum Tube section:
300 Watts into 2, 4 or 8 Ohms

Total Harmonic Distortion:
Solid State section:
0.005% maximum from 20Hz to 20kHz
Vacuum Tube section:
0.5% maximum from 20Hz to 20kHz

Signal to Noise Ratio:
Solid State section: 122dB
Vacuum Tube section: 112dB

Dynamic Headroom:
Solid State section: 1.8dB
Vacuum Tube section: 1.2dB

Damping Factor:
Solid State section: >40
Vacuum Tube section: >18

Frequency Response:
Solid State section:
+0, -0.25dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz
Vacuum Tube section:
+0, -0.5dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 70,000Hz

3 Balanced
3 Unbalanced
(1 each for Solid State, Vacuum Tube,
and Composite)

Overall Dimensions (W x H x D):
17-1/2” (44.45cm) x 13-1/4” (33.7cm)
x 29-1/2” (74.9m)

170 lbs (77.1 kg) net,
190 lbs (86.2 kg) in shipping carton