In addition to everything already mentioned, the MC451 comes with a multitude of other McIntosh amplifier the technologies:

• Power Guard^® that monitors and adjusts the input signal in the 300 Watt solid state amplifier section in real time, then makes inconspicuous volume adjustments to prevent harsh sounding distortion and potential speaker damaging clipping.
• Power Guard Screen Grid Sensor^® (SGS). The 150 Watt vacuum tube amplifier section features our 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.
• 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.
• A McIntosh Monogrammed Heatsink^™ that is connected to advanced high current output transistors to 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

• FTC Power Output Rating

  Solid State section: 300 W
  Vacuum Tube section: 150 W

• Power Output per Channel

  Solid State section: 300 W 2, 4 or 8 ohms
  Vacuum Tube section: 150 W into 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 20kHz

  Vacuum Tube section: 0.5% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20kHz

• S/N below rated output

  Solid State section: 118dB
  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 20kHz
  +0, -3dB from 10Hz to 100kHzVacuum Tube section:
  +0, -0.5dB from 20Hz to 20kHz
  +0, -3dB from 10Hz to 70kHz

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: Push-Pull Complementary
  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

  2 (1 Solid State or Mono, 1 Vacuum Tube)

• Front Panel

  Glass

• Illumination

  Direct LED

• Chassis Style

  Polished stainless steel & black painted steel

Weights & Dimensions

• Unit Dimensions (W x H x D)

  17-7/8″ (45.4cm) x 11-13/16″ (30cm) x 21-1/2″ (54.6cm)

• Unit Weight

  133 lbs (60.3 kg)

• Shipping Weight

  159 lbs (72.1 kg)