The McIntosh MC275 is not just another tube amplifier—it’s a classic. With its 75 watts per channel (150 W mono), transformer-coupled tube design, refined build, and musical character, it stands as one of the benchmarks for tube power amplification. It brings together the soul of vintage tube sound with engineered performance and reliability. For those who value sound, craftsmanship, and legacy, the MC275 remains a compelling choice in high-end audio.

Technical Composition

Tube Complement

• 8 total tubes

  • 4 × KT88 power output tubes

  • 4 × 12AX7A / 12AT7 small signal tubes (input & driver stages)

The KT88s are well-known for their combination of muscular dynamics and liquid midrange texture. McIntosh operates these tubes conservatively to ensure long life (typically thousands of hours).

Circuit Topology

The amplifier operates as a push-pull design, which reduces distortion and enhances power efficiency. Every signal path is fully tube-driven — no solid-state amplification stages are used in the signal chain.

The result is an amplifier that preserves musical nuances, offering effortless dynamics and tonal richness.

Key Features & Highlights

• Tube amplification with transformer-coupled output (Unity Coupled Circuit): The MC275 uses a fully tube signal path and tracked output transformers to deliver its power and ensure tonal purity and stability. 

• Stereo and Mono (Parallel) Modes: In stereo mode, the amplifier outputs 75 watts per channel (into 4, 8 or 16 ohms). In mono mode (bridge/parallel), it delivers 150 watts into 2, 4 or 8 ohms—offering flexibility depending on loudspeaker and system demands. 

• High-quality connections and real world usability: Balanced (XLR) and unbalanced (RCA) inputs, gold-plated Solid Cinch™ speaker terminals, sturdy chassis and excellent build quality — the MC275 is designed for long-term use, not just showroom appeal. 

• Tube status indicators & protection: The amplifier incorporates small signal tube LEDs to indicate operational status; if an output tube fails, real-time indication is provided. In addition, there is a Sentry Monitor™ protective circuit to safely disengage output if conditions exceed safe operating limits. 

• Timeless design and presence: The MC275’s design has become iconic: its polished stainless steel, black front panel, and glowing tube displays are as much part of the experience as the sound. Many owners consider it a piece of audio art as well as a power amplifier.

Technical Specifications

• Power Output: 150 watts per channel into 2, 4, or 8 ohms

• Number of Channels: 2 (stereo)

• Circuit Type: Vacuum tube amplifier using Unity Coupled Transformer

• Tube Complement: 8 × KT88, 4 × 12AX7A, 4 × 12AT7

• Total Harmonic Distortion (THD): ≤ 0.5% from 250 mW to rated power (20 Hz–20 kHz); < 0.20% at 1 watt

• Signal-to-Noise Ratio (S/N): 112 dB below rated output

• Dynamic Headroom: 1.2 dB

• Damping Factor: Greater than 18

• Frequency Response: +0 / -0.25 dB (20 Hz–20 kHz); +0 / -3.0 dB (10 Hz–70 kHz)

• Input Impedance: 20 kΩ balanced, 47 kΩ unbalanced

• Input Sensitivity: 2.5 V balanced / 1.25 V unbalanced for rated output

• Inputs: 2 balanced (XLR), 2 unbalanced (RCA)

• Speaker Outputs: Gold-plated Solid Cinch™ binding posts for 2, 4, and 8 ohm connections

• Power Requirements: 100V, 120V, or 230V AC depending on market

• Dimensions (W × H × D): 18.25″ × 10.25″ × 21″ (46.4 × 26 × 53.3 cm)

• Weight: 118 lbs (53.5 kg) net; 135 lbs (61.2 kg) shipping