McIntosh C100 (1997–2000)
A dual-chassis solid-state preamplifier with fully balanced circuitry and precision digital volume control
Overview
The McIntosh C100 is a stereo preamplifier manufactured from 1997 to 2000. It features a dual-chassis design, separating the control and power supply section from the signal path to reduce interference and preserve sound quality. Designed as a "Pure Audio Control Center," it supports both balanced (XLR) and unbalanced (RCA) audio inputs and outputs, with a fully balanced circuit architecture throughout. The unit includes a dedicated phono stage for both MM and MC cartridges, the latter using a specially developed silver-wire transformer housed in a mu-metal shield.
Specifications
| Frequency characteristic | 10 Hz ~ 40 kHz + 0 -0.5 dB |
| Rated output | 2.5 V (balanced / unbalanced, main, switched 1/2 respectively) |
| Output impedance | 100 Ω (Balanced) 50 Ω (unbalanced) |
| Maximum output voltage | 25.0 V (balanced main / switched output, 10 Hz to 40 kHz) 12.0 V (main / switched unbalanced output, 10 Hz to 40 kHz) |
| Total harmonic distortion factor | Maximum 0.002% (20 Hz to 20 kHz at rated output) |
| Input sensitivity | Phono : 4.4 mV (0.5 mV IHF at 2.5 V rated output) High Level : 450 mV (50 mV IHF at 2.5 V rated output) |
| S/N ratio (A-network) | Phono: 86 dB High Level: 98 dB |
| Maximum input signal | Phono MM: 50 mV High Level : 5 V (balanced) |
| Input impedance | Phono MM : 47 kΩ Phono MC : 5 Ω High Level (balanced) : 44 kΩ High Level (unbalanced) : 22 kΩ |
| Voltage gain | 70 dB (MC → Tape out) 40 dB (MM → Tape out) 0 dB (High Level → Tape out) 15 dB (High Level → Main out) |
| AC outlet | Switched : four systems Unswitched : 1 system |
| Power | AC100V |
| Power consumption | 25 W |
| External dimensions | 444 mm wide x 137 mm high x 445 mm deep per chassis |
| Weight | 11.0 kg (Control Part) 8.7 kg (Preamplifier Part) |
| Attachment | Wireless Remote Control |
Design
The C100 was McIntosh’s first dual-chassis preamplifier, with the upper chassis housing the low-noise power supply and remote control system, and the lower chassis dedicated to the signal path. A fully balanced circuit is used from input to output, with unbalanced signals converted to balanced for internal transmission. Each amplification stage has its own dedicated regulator, and critical components include low-noise metal-coated resistors and polypropylene capacitors. The phono stage features a newly developed transformer with silver wire coil for MC cartridges, enclosed in a mu-metal shield. Input switching and control functions are handled by a microprocessor and relays with ruthenium-evaporated contacts sealed in inert gas-filled glass tubes. A digital control attenuator provides volume accuracy within ±0.05 dB, adjusted via an optical rotary encoder with 128 steps per rotation. Volume and balance are displayed using a blue fluorescent tube, showing gain in 0.5 dB increments or as a percentage. The unit includes a source trim function, a processor input/output for connecting a graphic equalizer, and a resettable power switch to recover from microprocessor lockups.
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