Help Image

Talk with an Expert

Our knowledgeable advisers like Eddie Fields can help you choose and buy the gear you’ll love for years to come. Call, chat, or email us, or come by the showroom!

Chat with us

Overview

The Absolute Sound 2023 Product of the Year Award

The MC451 Dual Mono Amplifier joins the MC901 in offering the ultimate solution to bi-amping a loudspeaker. Like the MC901, the MC451 uses our Hybrid Drive™ technology that combines a separate vacuum tube and solid state amplifier onto one single chassis to produce the best possible sound performance from a bi-ampable speaker. Unlike the larger MC901, the MC451 has a more conventional McIntosh form factor and size, allowing it to fit into home audio systems, racks, and furniture more easily. Adding a pair of MC451s to your stereo system will allow your prized speakers to perform like never before.

McIntosh MC451 Amplifier

"I’ve heard enough systems and recordings to know that the midrange and treble nuances provided by the MC451 will improve the musicality of a very substantial number of high-end rigs and suit the personal taste of a wide range of audiophiles. It did an outstanding job amplifying every source I auditioned, from the latest LPs and SACD/DSD to high-resolution PCM recordings… Put as simply as possible, the MC451 sounds different enough to help redefine the state of the art for many high-end audiophiles." - The Absolute Sound

The MC451 is comprised of a 150 Watt vacuum tube amplifier and a 300 Watt solid state amplifier, which is more than enough power to drive virtually all speakers.

The vacuum tube section drives the speaker's midranges and tweeters, while the solid state section drives the woofers. The 150 Watt vacuum tube amplifier is powered by four KT88 output tubes which are located under a removable wire cage, plus two 12AT7 and one 12AX7A signal tubes; it uses our patented Unity Coupled Circuit output transformer to deliver its full 150 Watts into almost any speaker regardless if it has 2, 4 or 8 Ohm impedance.

Similarly, the 300 Watt solid state amplifier delivers its full 300 Watts into a 2, 4 or 8 Ohm impedance speaker via our Autoformer™ technology.

The two amplifiers in the MC451 are designed to work together in a synergistic relationship and are specifically engineered to assure that each only amplifies its intended frequencies. The large but quiet toroidal transformer generates enough power so that neither amplifier robs power or performance from the other. All of this results in easy bi-amping with unparalleled performance and sound reproduction from your speakers.

McIntosh MC451 Amplifier

Bi-amping your speakers with the MC451 is easy. No longer do you need fiddle with two separate amplifiers, an external crossover, and a lot of trial and error to properly configure the two separate amplifiers with often times only so-so results. The MC451 solves these hassles thanks to its internal, adjustable crossover. The MC451’s crossover tailors the output frequency range of each amplifier section to the attached loudspeaker. Simply set the CROSSOVER POINT knob on the back of the MC451 to the loudspeaker’s crossover point, then frequencies below the crossover point will be sent to the solid state amplifier and frequencies above it will be sent to the vacuum tube amplifier.

This adjustable crossover allows you to optimize the performance of both amplifier sections to your speaker's specifications and to your listening preferences. Gain levels for the vacuum tube amplifier can be adjusted from -6dB to +3dB. A direct feed can also be connected to each amplifier section, thus bypassing the internal crossover.

The MC451 features our DualView™ Power Output Meter. The DualView meter features two of our traditional, fast responding mechanical meters stacked above and below each other in a single meter window; one meter is dedicated to the 150 Watt vacuum tube amp and the other to the 300 Watt solid state amp. Each meter operates independently of the other and displays the real time power reading of each amplifier section.

McIntosh MC451 Amplifier

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

The uncompromising fit and finish of the MC451 is highlighted by familiar McIntosh design cues. The front features a signature black glass faceplate with three clear windows that allow viewing of the vacuum tubes, the DualView meter, two rotary control knobs, an illuminated logo and lettering, and built-in aluminum handles. The top is highlighted by a series of block diagrams printed on glass inserts outlining the circuitry and specifications of the unit. All of this sits atop of stainless steel chassis that's been polished to a pristine mirror finish.

McIntosh MC451 Amplifier

The MC451 amplifier can be combined with a variety of preamplifiers, turntables, CD players, media streamers, speakers, and other specialty products to form a complete home audio system designed for bi-amping loudspeakers. Contact your local dealer to learn more.

Specifications

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 100kHz

Vacuum 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)

Downloads

This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.

FAQs

Please read our FAQs page to find out more.

Do you price match?

Yes. We match any authorised dealer, including big-box retailers. If you find the same product at a lower price, contact us and we'll match it.

Do you offer free shipping?

Yes — free shipping on every order, with 2-day delivery available on most products. Easy returns and exchanges are included.

Where is your showroom?

We're at 6362 Alder Drive, Houston, Texas. The showroom lets you hear and compare reference-level systems in person before making any decisions. If you're considering a larger purchase or installation, it's well worth the visit.

Can I buy online without visiting the showroom?

Yes. The full product range is available through the online store with free nationwide shipping. For more complex system builds, speaking with one of our advisers first tends to lead to a better result.

Do you offer financing?

Yes. Special financing is available through the BrandSource Credit Card for qualifying purchases, allowing you to spread payments over time with no annual fee. Promotional rebate savings are also available periodically. See the financing page for full details.

Do you install systems as well as sell equipment?

Yes — installation is central to what we do. We design and install whole-home audio and video, home theaters, media rooms, outdoor audio, lighting and motorised shades, and full smart home automation.

Do you provide support after installation?

Yes. We provide ongoing service and support to ensure systems continue performing as intended — not just on installation day, but over the long term.