McIntosh MC275 Audiophile Stereo Vacuum Tube Power Amplifier

Upon its initial release in 1961, the MC275 Vacuum Tube Amplifier became an instant favorite due to its ability to drive the power-hungry speakers of that time period with great power at low distortion levels. However, as transistors emerged and vacuum tubes became 'old technology,' the MC275 was discontinued in 1971. Thankfully, that is not where the story of the MC275 ends.

It came back into production as a special commemoration edition in 1993 to posthumously honor McIntosh co-founder and longtime president Gordon Gow. The reincarnated MC275 received incredibly high acclaim and earned its spot back in the product lineup. The overall storyline behind the MC275 and its history with McIntosh is exceptionally rich and it has been the driving force behind countless home audio systems for decades. It is hard to imagine McIntosh without the MC275.

Now in its sixth generation, the MC275 has many subtle enhancements from the previous releases that have greatly improved performance. Combined with the widest bandwidth McIntosh output transformer design, the MC275 features tauter bass control and thermally quiet circuit design. The result is pure music. This vacuum tube power amplifier has all the features to meet the needs of today’s music enthusiast, while preserving the qualities that have made the MC275 the most revered McIntosh vacuum tube amplifier.

The MC275 can be used in either stereo or mono mode. When used as a stereo amplifier, it will deliver 75 Watts per channel to 4, 8 or 16 Ohm speakers; in mono mode it will output 150 Watts to a single speaker with an impedance of 2, 4 or 8 Ohms. The MC275's full power can be delivered regardless of the speaker impedance thanks to our patented Unity Coupled Circuit output transformer technology – the same technology McIntosh was founded on in 1949. The two Unity Coupled Circuit output transformers are located next to the power transformer.

Four KT88 vacuum tubes power the output section while four 12AT7 and three 12AX7A smaller vacuum tubes are used for the Input, Voltage, and Driver amps. The MC275 offers both balanced and unbalanced inputs to connect to your preamplifier and home audio system. It comes with our fuse-less Sentry Monitor™ short-circuit protection that disengages the output stage before current exceeds safe operating levels and then resets automatically when operating conditions return to normal. Our patented gold-plated Solid Cinch™ speaker binding posts assure the best connection to all speaker cables.

The seven small tubes are LED illuminated to indicate the amplifiers functional status: upon power up, they sequentially glow amber for a few seconds and then all turn green to signify system readiness. In the rare case of an output tube failure, the small tube(s) in front of it will turn red to notify you of the problem. An input and output for our Power Control technology allows other connected McIntosh components, such as preamplifiers, CD players, turntables, or media steamers, to automatically turn on and off.

Features

• This tube power amplifier has all the features to meet the needs of today’s music enthusiast, while preserving the qualities that have made the MC275 the most revered McIntosh tube amplifier.
• This sixth generation MC275 has many subtle enhancements from the previous release that greatly improve performance. Combined with the widest bandwidth McIntosh output transformer design, the MC275 features tauter bass control and thermally quiet circuit design. The result is pure music.
• McIntosh patented, gold plated, speaker binding posts assure the best connection to all speaker cables, while high quality balanced and unbalanced input connectors enhance signal transfer from the connected preamplifier. 
• The seven small tubes are LED illuminated to indicate the amplifier’s functional status. Power Control is used to remotely control tube illumination from a McIntosh preamplifier.

Specifications

• Power Output per Channel

  75W @ 4, 8 or 16 Ohms

• Number of Channels

  2

• Total Harmonic Distortion

  0.5% maximum harmonic distortion at any power level from 250 milliwatts to rated power, 20Hz to 20,000Hz
  (≤ 0.25% harmonic distortion at 1kHz)

• S/N below rated output

  105dB

• Dynamic Headroom

  1.2dB

• Damping Factor

  >22

• Rated Power Band

  20Hz to 20kHz

• Frequency Response

  +0, -0.5dB from 20Hz to 20,000Hz
  +0, -3.0dB from 10Hz to 100,000Hz

CONTROL

• Remote Power Control

  Yes, input and output

• Multi-Channel DB25 Cable

  No

GENERAL SPECIFICATIONS

• Circuit Configuration

  Unity Coupled

• Circuit Design

  Vacuum Tube

• Mono Bridge

  Yes

• Mono Parallel

  Yes, 150W @ 2, 4 or 8 Ohms

• Output Type

  Unity Coupled Output Transformer

• Meters

  No

• Meter Light Switch

  Small signal tubes LEDs controlled by McIntosh preamp

• Balanced Input

  Yes

• Front Panel

  N/A

• Illumination

  Small Signal Tubes, LED

• Chassis Style

  Polished Stainless Steel

CONNECTIVITY

• Speaker Binding Post Type

  Patented Solid Cinch™ Speaker Binding Posts

WEIGHTS & DIMENSIONS

• Unit Dimensions (W x H x D)

  16-1/2" (41.9cm) x 8-1/2" (21.6cm) x 12" (30.5cm)

• Unit Weight

  67 lbs (30.5 kg)

• Shipping Weight

  75 lbs (34.1 kg)

Support

• Datasheet
• Manual
• Power Amp Comparison Chart