Clean unit, well taken care of. The unit is 40 years old and has never been serviced. What are the specs for the McIntosh MX 113? Frequency response: 20Hz to 20kHz Total harmonic distortion: 0.1% Gain: 62dB (MM), 20dB (line) Input sensitivity: 2mV (MM), 250mV (line) Signal to noise ratio: 72dB (MM), 85dB (line) Output: 250mV (line), 2.5V (Pre out), 10V (Pre out Max) Semiconductors: 2 x JFET, 3 x MOSFET, 30 x transistors, 31 x diodes, 2 x IC Dimensions: 16 x 5.4 x 15 inches Weight: 26 lbs. What else to know about the McIntosh MX 113? The McIntosh Tuner-Preamplifier unit concept accommodates all regular inputs of tuner, phono, tape, etc. And allows the selection of the right power amplifier needed for your system. Multiple “selectivity” switchable from the front panel. An elegant solution to a tough problem. Linear Phase (constant delay) IF amplifier for low distortion at even high selectivity and low distortion. Steggered tuning condenser elements to improve RF front and behavior, less interstage coulping, lower spurious effect, higher Q circuits. Tremendous accomodiation of strong RF input signals – up to 10 volts without overload – overcoming an aggravating limitation of conventional tuners. Highest spurious rejection 90 dB (IHF) and highest image rejection 95 dB (88 to 108 MHz). This means you receive the stations at the right place on the dial only. You don’t receive the same stations or some mixture as you tune across the dial. Ultra Sonic “muting” provides smooth inter channel FM noise suppression. Has complete connection to McIntosh Maximum performance Indicator to maximize your listening pleasure. McIntosh developed a special detecting circuit used in the multiplex section. An advantage of this circuit is the elimination of the critical adjustments necessary with commonly used matrixing circuits. The circuit detects the L – R side-bands, then automatically matrixes the recovered information with the L + R carrier signal. This yialds the left and right program output with maximum separation. TUNING MECHANISM AND DIAL DRIVE. In the MX 113, the unique design and careful manufacture of the mechanical assembly gives smooth flywheel tuning. By controlling the relationship of mass and mechanical resistance, and by dividing the workloads in the dial drive system, it becomes nearly impossible to detect any backlash. Yet, the entire dial drive is a model of mechanical stability. For added ease and increased tuning accuracy, a section of the dial pointer is illuminated. A seven-section variable capacitor is the heart of the RF section. Spurious responses are significantly reduced. The four FM sections of the variable tuning capacitor provides a high degree of RF selectivity and excellent spurious rejection. Using the latest “state of the art” field effect transistors with a welldesigned variable tuning capacitor has provided the MX 113 with an excellent RF front-end. FM-IF AND DISCRIMINATOR SECTION. The MX 113 uses linear-phase IF filters. Each filter was designed from a FORTRAN computer program for minimumphase and constant delay. The mathematical complexity of the filter design procedure is almost beyond belief. Using numerical integration in the S-Plane, an “IBM” 1130 high speed computer spent eighteen minutes on the mathematics for the design of the IF filter. It would have taken a human engineer, working twenty-four hours a day, seven days a week, and working error-free three-hundred years to perform the same mathematical calculations! FM STEREO MULTIPLEX SECTION. Mclntosh has developed a special detecting circuit used in the multiplex section. A particular advantage of this circuit is the elimination of the critical adjustments necessary with commonly used matrixing circuits. The circuit detects the L – R sidebands, then automatically matrixes the recovered information with the L + R carrier signal. This yields the left and right program output with maximum separation. A three section variable capacitor is used for greater spurious rejection. The RF amplifier is unique. This circuit design achieves equal sensitivity even at the low end of the band. Spurious, image, and intermediate frequency rejection are all superior. The same circuit delivers equal selectivity across the entire band. Distortion at low audio frequencies is minimized by using two AVC filter sections instead of the conventional one. There are three transistors in each channel of the phono preamplifier. The feedback loop reduces noise and distortion. It also provides precision RIAA frequency compenation required for magnetic phonograph cartridges. Feedback remains in effect even at 20 Hz, where gain is highest. L + R AMPLIFIER. The L + R amplifier consists of a single transistor connected as a voltage amplifier. The power supply of the MX 113 has received very special attention. Three separate rectifier circuits are used. First, a fullwave rectifier supplies DC to all audio circuits. The second full-wave rectifier supplied DC to all tuner and multiplexdecoder circuits. The power supplies are elaborate in design. They use electronic filtering to insure the lowest possible background hum level, maximum stability, and extremely good regulation. From McIntosh Brochure. Brief History of McIntosh. Long mapped-to Binghamton New York the current headquarters and manufacturing center for McIntosh Labs not many people know the brand was originally launched outside of the Nations Capital in Silver Spring Maryland, in 1949. In 1956, the brand built their original facility in New York, according to the official brand website. The item “McIntosh MX 113 Stereo AM FM Tuner Preamplifier MX113- Vintage Classic” is in sale since Wednesday, July 14, 2021. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Preamps & Tube Preamps”. The seller is “jwigm” and is located in Raleigh, North Carolina. This item can be shipped to United States.

• Brand: McIntosh
• Model: McIntosh MX 113
• Country/Region of Manufacture: United States

Tags: classic, mcintosh, mx113, preamplifier, stereo, tuner, vintage