While an entirely new design, the MC901 comes with the technology one would expect from a McIntosh amplifier:

• Power Guard^® that monitors and adjusts the input signal in the 600 Watt solid state amplifier section in real time, then makes unobtrusive adjustments to prevent harsh sounding distortion and potential speaker damaging clipping.
• Power Guard Screen Grid Sensor™ (SGS). The 300 Watt vacuum tube amplifier section of the MC901 breaks new ground as it's our first amplifier to feature our new Power Guard SGS™ technology. Power Guard 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, a circuit in Power Guard SGS is activated which then dynamically attenuates the input signal in real time to keep the vacuum tubes operating at safe levels.
• Sentry Monitor™ observes the output current and shuts the amplifier off if it ever exceeds safe limits.
• Quad Balanced design that cancels virtually all noise and distortion that may have crept into the audio signal.
• Power Control that can send power on/off signals to other connected McIntosh components for easy system power up and shutdown.
• Our patented, gold-plated Solid Cinch™ speaker binding posts that easily and securely attach the speaker cables.
• McIntosh Monogrammed Heatsinks™ that are connected to advanced high current output transistors efficiently cool the solid state amplifier section.
• Our Power Management System that will turn the entire unit off after a set amount of time when no input signal has been detected.

Electronic Specifications

• Power Output per Channel

  - Solid State section: 600 Watts @ 2, 4 or 8 Ohms
  - Vacuum Tube section: 300 Watts @ 2, 4 or 8 Ohms

• Number of Channels

  1

• Total Harmonic Distortion

  - Solid State section: 0.005% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20,000Hz
  - Vacuum Tube section: 0.5% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20,000Hz

• S/N below rated output

  Solid State section: 122dB
  Vacuum Tube section: 112dB

• Dynamic Headroom

  Solid State section: 2.5dB
  Vacuum Tube section: 1.2dB

• Damping Factor

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

• Rated Power Band

  Solid State section: 20Hz to 20kHz
  Vacuum Tube section: 20Hz to 20kHz

• 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

Control 

• Remote Power Control

  Yes

• Multi-Channel DB25 Cable

  N/A

Connectivity

• Speaker Binding Post Type

  Patented Solid Cinch™ Speaker Binding Posts

General Specifications

• Circuit Configuration

  Solid State section: Quad Balanced
  Vacuum Tube section: Unity Coupled

• Circuit Design

  Solid State and Vacuum Tube

• Mono Bridge

  No

• Mono Parallel

  No

• Output Type

  Solid State section: Autoformer™
  Vacuum Tube section: Unity Coupled Output Transformer

• Meters

  DualView™ Power Output Meter

• Meter Light Switch

  Yes

• Balanced Input

  3 (1 Solid State, 1 Vacuum Tube, 1 Composite)

• Front Panel

  Glass

• Illumination

  Direct LED

• Chassis Style

  Polished stainless steel & black painted steel

Weights & Dimensions

• Dimensions (W x H x D)

  17-1/2" (44.45cm) x 13-1/4" (33.7cm) (including feet) x 29-1/2" (74.9m)

• Weight

  180 lbs (81.6 kg)

• Shipping Weight

  200 lbs (90.7 kg)