McIntosh C40 (1993)

Name: McIntosh C40
Brand: McIntosh

A solid-state audio control center with built-in monitor amplifier, released in March 1993

Overview

The McIntosh C40 is an audio control center and preamplifier from McIntosh Laboratory. It has a built-in 20W + 20W monitor amplifier, so it can drive speakers directly. It came out in March 1993. It has eight unbalanced inputs, processor loops, and a 5-band equalizer with ±12 dB adjustment. All signal switching runs through digital logic-controlled reed relays. The monitor amplifier has Power Guard protection to prevent distortion.

Specifications

Year of Production	1993
Product type	Audio control center / Preamplifier (with built-in monitor amplifier)
Frequency response	20 Hz to 20,000 Hz, +0 -0.5 dB
Rated output	2.5 V (main, balanced output)
Output impedance	600 Ω (main, balanced output)
Maximum output voltage	8 V (main, balanced output, 20 Hz to 20,000 Hz)
Total harmonic distortion	0.002% maximum (20 Hz to 20,000 Hz at rated output)
Input sensitivity Phono	2.5 mV (at 2.5 V rated output)
Input sensitivity High level	250 mV (at 2.5 V rated output)
Signal-to-noise ratio (A-weighted) Phono	90 dB (for input up to 10 mV)
Signal-to-noise ratio (A-weighted) High level	105 dB (below rated output)
Maximum input signal Phono	90 mV
Maximum input signal High level	10 V
Input impedance Phono	47 kΩ, 65 pF
Input impedance High level	22 kΩ
Voltage gain Phono → Tape	40 dB
Voltage gain High level → Tape	0 dB
Voltage gain Phono → Main	60 dB
Voltage gain High level → Main	20 dB
Equalizer control	5-band, ±12 dB at 30 Hz, 150 Hz, 500 Hz, 1.5 kHz, 10 kHz
Monitor Amplifier Section Output	20 W + 20 W (8 Ω, 20 Hz-20,000 Hz)
Monitor Amplifier Section Total harmonic distortion	0.005% maximum (250 mW to rated output)
Monitor Amplifier Section Frequency response	20 Hz to 20,000 Hz, +0 -0.5 dB
Monitor Amplifier Section Input Sensitivity / Impedance	750 mV / 27 kΩ
Monitor Amplifier Section Signal-to-noise ratio (A-weighted)	100 dB (below rated output)
AC power outlets	4 switched, 1 unswitched
Power requirements	100 VAC, 50 Hz/60 Hz
Power consumption	25W ~ 58W
Dimensions (W x H x D)	445 x 137 x 432 mm (including terminals)
Panel operating clearance	38 mm
Weight	12 kg

Design

All signal switching in the C40 goes through sealed reed relays under digital logic control. The 5-band equalizer gives ±12 dB boost or cut, and the center position bypasses the circuit for flat response. A compander system has expansion and compression modes for dynamic range compensation. The active loudness control adjusts independently of the master volume. The phono equalizer uses 1% tolerance resistors to keep RIAA deviation low. The front panel is glass with gold and teal blue lighting. An optional SCR-3 relay unit handles speaker switching and amplifier power control, and an external input terminal lets you hook up surround amplifiers. In the built-in monitor amplifier, the Power Guard circuit compares input and output waveforms and reduces level to prevent distortion.

Product Family

McIntosh lists the C40 as a "Classic Model" and a "Preamplifier."

Market Value

┌──────────────────────────────────────────────────────────────────────────┐
│ MCINTOSH C40                                                    Nov 2026 │
├──────────────────────────────────────────────────────────────────────────┤
│ High      $2,380                                  Latest          $2,190 │
│ Median    $2,350                                  Trend                — │
│ Low       $2,190                                  Volume           ~1/mo │
├──────────────────────────────────────────────────────────────────────────┤
│ $3,000 ┤                                                                 │
│        │                                                                 │
│        │                                                                 │
│ $2,571 ┤                                                                 │
│        │                                                                 │
│        │.                       .                                        │
│        │                                                                .│
│ $2,000 ┤                                                                 │
│        ├─────────────────────────────────────────────────────────────────│
│    vol │█                       █                                       █│
│        └─────────────────────────────────────────────────────────────────│
│         2026-02                      2026-03                      2026-05│
└──────────────────────────────────────────────────────────────────────────┘

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