McIntosh MX113 Tuner-Preamplifier
McIntosh's AM/FM tuner and full preamp share one chassis and one glass faceplate. The phono stage is quiet.
Period listings, such as those in Audio (March 1988, p.110), show that MX-series McIntosh tuner-preamplifiers like this one continued to trade on the used market long after their introduction, alongside other classic high-end components of the era.
Overview
Reach behind an MX113 and count the jacks. Two phono inputs, each rated at 2 millivolts for 2.5 volts of output at 1 kHz. Aux and tape inputs at 0.25 volts for the same output. A main output that will swing up to 10 volts without distortion, and a tape output that turns a 10-millivolt phono signal into 1.2 volts. This is not a tuner with a volume knob bolted on. It's a full control center, and the tuner is the bonus.
The preamp section is where the MX113 earns its keep. Frequency response holds within +0.5 dB from 20 Hz to 20,000 Hz, and distortion stays below 0.1% at 2.5 volts across the same band. Hum and noise sit 72 dB below a 10-millivolt phono input, and 85 dB below rated output on the high-level inputs. The tone controls have real range: bass runs from -18 dB to +16 dB at 20 Hz, and treble reaches +20 dB at 20,000 Hz. There's a low-frequency filter that rolls off below 50 Hz and is down 12 dB at 20 Hz, and a high-frequency filter that rolls off above 5,000 Hz and is down 12 dB at 20,000 Hz. A center-channel output is provided at 2 volts with rated input to both channels, so this was designed for systems, not just stereo pairs.
The FM section is the reason a lot of these still get used. Useable sensitivity is 2.5 microvolts at 100% modulation (±75 kHz deviation) for 3% total noise and harmonic distortion IHF, with a 70 dB signal-to-noise ratio below 100% modulation and a 1.5 dB capture ratio. Harmonic distortion holds under 0.3% in mono and under 0.5% in stereo. Audio frequency response is ±1 dB from 20 Hz to 15,000 Hz with standard 75-microsecond de-emphasis and the 19,000 Hz pilot filter engaged. Stereo separation measures 35 dB at 1,000 Hz. Selectivity is switchable, and the numbers show why. In NORMAL, adjacent-channel selectivity is 6 dB minimum IHF and alternate-channel is 58 dB minimum. In NARROW, adjacent jumps to 15 dB and alternate to 88 dB. Image rejection runs 95 dB minimum from 88 to 108 MHz, and spurious rejection is 90 dB IHF minimum. The SCA filter offers 50 dB rejection from 67 kHz to 74 kHz on a 275 dB-per-octave slope.
AM isn't an afterthought here, which is unusual for the period. Sensitivity is 75 microvolts IHF with an external antenna, signal-to-noise is 45 dB IHF minimum and 55 dB at 100% modulation, and harmonic distortion does not exceed 1% at 30% modulation. Image rejection is 65 dB minimum across 540 kHz to 1600 kHz. The same NORMAL/NARROW switch changes the AM bandwidth too. Frequency response is 3.5 kHz at -6 dB in NORMAL and 2.1 kHz at -6 dB in NARROW, with adjacent-channel selectivity of 35 dB minimum IHF in NORMAL and 45 dB minimum in NARROW.
One thing to know before buying: McIntosh issued a modification for all units with serial numbers below 400H1, intended to reduce sensitivity to RF interference. It targets CB and HAM apparatus bleeding in while the unit operates in Phono mode, along with interference from manmade noise sources like refrigerators and passing cars. Ask whether a given example has had it applied, because that kind of service note gets lost over decades. Alignment is a real consideration too. McIntosh's own service documentation specifies a test bench that includes an AM signal generator, an FM signal generator, a VTVM, a multiplex generator, a 10.7 MHz sweep generator, a crystal-controlled 10.7 MHz generator, an oscilloscope, a harmonic distortion analyzer, and a 10.7 MHz ±75 kHz sweep marker generator. It states plainly that if the necessary equipment isn't available, alignment should not be attempted.
Documentation for the MX113 is unusually complete by vintage standards. The manual includes full alignment instructions with the AM-FM-MPX sequence spelled out, schematic notes covering resistance and capacitance conventions, and a replacement parts list with McIntosh part numbers. Transistors, fuses, potentiometers, switches, and transformers are all itemized, from the volume control to the FM IF transformers to the power transformer. McIntosh's customer service department in Binghamton, New York is listed in the manual as the source for replacement parts ordered by number.
What the MX113 isn't: a receiver. There's no power amplifier inside, so it needs to feed a separate McIntosh power amp or an equivalent. Collectors drawn to the MX113 usually already own the amp, or plan to. What it is: a tuner-preamplifier built to the same standard as the separates it replaced, with a phono stage that handles two turntables, tone controls with real range, and an FM front end with switchable selectivity that still earns its place in a modern system. The glass faceplate and the illuminated tuning meter are the parts people photograph. The 72 dB phono hum-and-noise figure is the part that keeps it plugged in.
Market Value
┌──────────────────────────────────────────────────────────────────────────┐ │ MCINTOSH MX113 Nov 2026 │ ├──────────────────────────────────────────────────────────────────────────┤ │ High $1,095 Latest $1,095 │ │ Median $1,067 Trend — │ │ Low $497 Volume ~2/mo │ ├──────────────────────────────────────────────────────────────────────────┤ │ $2,000 ┤ │ │ │ │ │ │ │ │ $1,314 ┤ │ │ │ .│ │ │ . │ │ │ │ │ $400 ┤. │ │ ├─────────────────────────────────────────────────────────────────│ │ vol │█ █ █│ │ └─────────────────────────────────────────────────────────────────│ │ 2026-02 2026-04 2026-05│ └──────────────────────────────────────────────────────────────────────────┘
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eBay Listings
Recently sold on eBay: $497–$1,095 (median $1,067, based on 3 completed sales, past 12 months)
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