McIntosh MX 117

 

 

The MX 117 AM-FM Stereo Tuner-Preamplifier concept is a total Mclntosh master control center that allows you to select the matching Mclntosh power amplifier for your individual requirements. All needed inputs such as two record players, two tape recorders and auxiliary can be accommodated, along with the built-in AM-FM stereo tuner. The advanced circuits and performance features of the Mclntosh MX 117 make it an ideal and especially convenient solution for the most discriminating stereo listener.

FM AFL AUTOMATIC FREQUENCY LOCK

The Automatic Frequency Lock is a patented Mclntosh circuit that activates when you tune to the center frequency of an FM station. A varacter diode fine tunes the tuner with a correction voltage from the AFL circuit. When the center ON -station vertical LED indicator lights, the AFL circuit is in operation and the tuner stays locked to the signal. There will be no drift from this accurate tuning, insuring minimum distortion and best overall FM performance.

2. ELECTRONIC FET ANALOG INPUT SWITCHING

All critical input switching is done electronically using field effect transistor analog switches. The front panel selector simply switches small amounts of control DC voltage which turn the FET analog switches on or off. Since the FET analog switches are located near the input jacks, the length of interconnecting leads is much shorter. This design eliminates switching noise as well as frequency loss caused by the longer signal leads necessary in conventional circuits.

3. HEADPHONE—OUTPUT AMPLIFIER

The built-in headphone amplifier is capable of driving a pair of dynamic headphones with less than 0.02% harmonic distortion. Because of its extremely low distortion and power capability, it is also the main preamplifier output.

4. TRI-FREQUENCY PROGRAM EQUALIZER

Three separate controls allow the balance and response of musical information to be adjusted with far more flexibility than with conventional tone controls. The center frequencies of the controls are 30 Hz, 750 Hz and 10 kHz. Plus and minus 12 dB of control is available. Use of the program equalizer controls does not affect in the slightest the low noise, low distortion performance of the tuner-preamplifier. When the equalizer controls are in their center detent or flat position, their action is neutral and response of the tuner-preamplifier is absolutely flat.

5. TRUE LOUDNESS COMPENSATION

The MX 117 active circuit loudness control is continuously variable with constant midrange gain and operates independently of the volume control. The loudness contour is accurately modeled after the Fletcher Munson family of "Equal Loudness" curves. Use of this control restores proper perceived frequency response at even the softest listening levels.

5. TRUE LOUDNESS COMPENSATION

The MX 117 active circuit loudness control is continuously variable with constant midrange gain and operates independently of the volume control. The loudness contour is accurately modeled after the Fletcher Munson family of "Equal Loudness" curves. Use of this control restores proper perceived frequency response at even the softest listening levels.

5. TRUE LOUDNESS COMPENSATION

The MX 117 active circuit loudness control is continuously variable with constant midrange gain and operates independently of the volume control. The loudness contour is accurately modeled after the Fletcher Munson family of "Equal Loudness" curves. Use of this control restores proper perceived frequency response at even the softest listening levels.

6. PRECISION TRACKING VOLUME CONTROL

The volume control manufactured for Mclntosh Laboratory is a step attenuator which has tracking accuracy within 1 dB throughout its entire range. Such extremely accurate matching is achieved through electronically controlled trimming of the resistance material deposited on pairs of miniature printed circuits. Tracking accuracy and quiet performance are permanently maintained.

Use does not affect performance as in ordinary volume controls.

7. ELECTRONIC FET RF SELECTIVITY SWITCHING

A back panel switch gives additional FM RF selectivity for best performance in areas with extremel strong station signal strengths. This switch feeds a control DC voltage to PIN semiconductor diodes which electronically perform the RF switching functions.

AUTOMATIC STEREO NOISE SUPPRESSION

A new third generation phase locked loop stereo decoder incorporates a unique variable stereo separation - noise reduction control circuit. This circuit operates from the IF amplifier signa strength detector. When listening to weak or distant FM stations, optimum stereo separation and signal to noise ratio is automatically provided. You get a smooth transition between stereo and mono depending on the prevailing signal conditions. This means that with the Mclntosh MX 117 you always get the most noise-free reception of weaker stereo signals. Since this circuit automaticallyadjusts in varying amounts, you never hearthe abrupt switching present in conventional circuits.

UNIQUE AM TUNER SECTION

The AM circuit in the MX 117 is unique in designfor a superheterodyne tuner. The AM RF amplifier circuit has constant selectivity, constant sensitivity and high image rejection across the complete AM band. In addition there is no loss of audio frequency response at the low end of the band. No conventional AM circuit can offer all these features simultaneously. These advanced AM performance characteristics of the MX 117 bring about a re-discovery of AM listening.

INTEGRATED CIRCUIT OPERATIONAL AMPLIFIERS

Both the magnetic phono and the equalizer amplifierstages utilize new high technology integrated circuit operational amplifiers. Noise factors are incredibly low and distortion levels are at or below the limits of the best present day test equipment.

 

PREAMP SECTION

FREQUENCY RESPONSE:  + 0 - 0.5 db from 20 Hz to 20 kHz

RATED OUT PUT LEVELS

Main Out : 2.5V

Line Out : 1.25V

Headphone : 750mV

Tape Out : 250mV

DISTORTION:  0.02% maximum at 2.5V output from 20 Hz to 20 kHz

INPUT SENSITIVITY AND GAIN

Input to Main Out

Phone 1 and 2:  2.2mV in for 2.5V out (61.1 dB gain at 1 kHz)

AUX, Tape 1 and 2: 250mV in for 2.5V out (20 dB gain at 1 kHz)

Input to Line Out

Phono 1 and 2 : 2.2mV in for 1.25V out (55 dB gain at 1 kHz)

AUX, Tape 1 and 2 : 250mV in for 1.25V out (14 dB gain at 1 kHz)

Input to Headphone Out

Phono 1 and 2:  2.2mV in for 750mV out (50.7 dB gain at 1 kHz)

AUX, Tape 1 and 2 250mV in for 750mV out (9.5 dB gain at 1 kHz)

Input to Tape Out

Phono 1 and 2:  2.2mV in for 250mV out (41.1 dB gain at 1 kHz)

AUX, Tape 1 and 2:  25pmV in for 250mV out (0 dB gain at 1 kHz)

SIGNAL TO NOISE

Phono 1 and 2:  -90 dB IHF A-weighted, below 10mV input -80 dB unweighted, below 10mV input

AUX, Tape 1 and 2:  - 100 dB IHF A-weighted, below 250mV input

-90 dB unweighted, below 250mV input

INPUT IMPEDANCE

Phono 1 and 2:  47kl2 and 50pF

AUX, Tape 1 and 2:  47kohm

OUTPUT IMPEDANCE

Main Out:  less than 100ohm (to operate into 5kohm or greater)

Line Out:  600ohm (to operate into a 600ohm line)

Headphone:   8ohm

Tape Out:  less than 200ohm (to operate into 5kohm or greater)

EQUALIZER CONTROL RESPONSE

Center Frequencies :  30, 750, and 10 kh

Boosr and Cut:  ± 12 dB

AM SECTION

SENSITIVITY.  75μV IHF with external antenna

SIGNAL TO NOISE RATIO:  45 dB minimum IHF or 55 dB at 100% modulation

FREQUENCY RESPONSE:  + 0 ~ 6 dB from 20 Hz to 3500 Hz

HARMONIC DISTORTION:  0.8% maximum at 30% modulation

ADJACENT CHANNEL SENSITIVITY:  30 dB minimum IHF

IMAGE REJECTION:  65 dB minimum from 540 kHz to 1600 kHz

FM SECTION

USABLE SENSITIVITY:  2μV (11.2dBf) IHF

QUIETING SENSITIVITY:  5μV(19.1dBf) IHF -50dB(Mono);  50μV (39.5dBf) IHF -50 dB (Stereo)

SIGNAL TO NOISE RATIO  :70 dB IHF minimum both Mono and Stereo

HARMONIC DISTORTION

0.18% (Mono) IHF maximum

0.38% (Stereo) IHF maximum

ALTERNATE CHANNEL SELECTIVITY:  75 dB IHF minimum

IMAGE REJECTION:  100 dB IHF minimum

STEREO SEPARATION:  45 dB minimum at 1 kHz

GENERAL INFORMATION

POWER REQUIREMENT:  120 Volts 50/60 Hz, 45 Watts

SEMI CONDUCTOR COMPLEMENT

24 Bipolar Transistors

18 Field Effect Transistors

62 Diodes

24 Integrated Circuits

MECHANICAL

MECHANICAL INFORMATION

SIZE

Front panel measures 16 inches wide (40.6 cm) by 5 7/16 inches high (13.8 cm). Chassis measures 14 3/4 inches wide (37.5 cm) by 4 13/16 inches high (12.2 cm) by 13 inches deep (33 cm), including connectors. Knob clearance required is 1 1/4 inches (3.2 cm) in front of mounting panel.

FINISH:

Front panel is anodized gold and black with special  gold/teal nomenclature illumination. Chassis is black.

MOUNTING::  Exclusive Mclntosh developed professional PANLOC.

WEIGHT::  24 pounds (10.9 kg) net, 36 pounds (16.3 kg) in shipping carton.