McIntosh MX112

At 25 lbs, it sits on the rack like a vault—dense, deliberate, and humming with the promise of FM fidelity from an era when tuning in was an event.

Overview

The McIntosh MX112 isn’t a powerhouse amplifier or a standalone tuner—it’s both, fused into one formidable slab of late-1960s audio engineering. Marketed as a solid-state stereo tuner preamplifier, it This was a preamp for those who wanted surgical tone adjustment, clean phono stages, and the confidence that every microvolt from the antenna would be handled with precision.

Despite its dual role, the MX112 carries no power amplifier section; it’s strictly a line-level conductor, routing signals from turntable, tuner, or auxiliary sources to a downstream amplifier. Its design prioritizes signal integrity: high-level inputs float at 100K ohms, minimizing loading on source devices, while the phono stage is tailored for standard MM cartridges with a 47K ohm input impedance and 100pF capacitance. The inclusion of traditional bass and treble controls suggests McIntosh anticipated real-world room acoustics and less-than-ideal speaker placement—offering corrective tools without sacrificing tonal neutrality. The loudness contour, applying +7 dB at 100Hz and +5 dB at 10kHz, further indicates a focus on low-level listening accuracy, compensating for the ear’s reduced sensitivity in the bass and treble at softer volumes.

Specifications

Key Features

Solid-State Tuner with IHF-Grade Sensitivity

The FM section of the MX112 is its technical standout, rated at 1.8 µV sensitivity under IHF standards— This meant it could pull in weaker stations with usable signal-to-noise performance, a critical advantage for listeners outside major metro areas. The 80 dB alternate channel selectivity ensured strong rejection of adjacent stations, reducing crosstalk and interference, while the 1.0 dB capture ratio indicates excellent ability to lock onto the dominant signal in multipath environments. The frequency response extends to 15kHz, preserving much of the high-frequency detail broadcast via FM, and the 0.15% THD figure suggests minimal distortion in the demodulated audio path. Together, these specs paint a picture of a tuner engineered not just for reception, but for high-fidelity playback.

Phono Stage with High Overload Margin

The phono input, calibrated for 2.5 mV output cartridges, includes a healthy 200 mV overload margin—meaning it can handle transients and high-output records without clipping. This headroom was likely intentional, accommodating everything from dynamic orchestral recordings to heavily modulated rock LPs without distortion. The 80 dB signal-to-noise ratio is indicating a quiet background when playing well-maintained vinyl. Paired with the standard 47K ohm loading, it was requiring no user adjustments for impedance matching.

The ±12 dB range at 20Hz and 20kHz provides substantial reach, enabling serious bass reinforcement or treble taming when needed.

High-Pass and Low-Pass Filters

The inclusion of switchable high and low filters—6 dB/octave at 10kHz and 50Hz respectively—hints at practical system integration. The high-pass (low-cut) filter could reduce tape hiss or sibilance, while the low-pass (high-cut) might tame FM noise or protect inefficient tweeters. These are gentle slopes, not surgical tools, but their presence underscores the MX112’s role as a system manager, capable of tailoring signals before they reach the power amp.

Collectibility & Value

Current market listings show a wide spread in pricing, with examples selling from $2,990 to $4,490 when restored and sold by specialist dealers. One European listing asked €2,299.99, while informal forums mention offers around $1,250—indicating condition and provenance heavily influence value. Collectors note common issues: cracked glass dials, non-functional tuning bulbs, and channel imbalance in the original volume control, which some have replaced with modern units—though reportedly with less-than-ideal taper response. The flickering stereo indicator light is a known alignment issue, often requiring professional servicing. Given the lack of DIY-friendly documentation and the precision needed for tuner alignment, repairs are generally not recommended for novices.

eBay Listings

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