McIntosh MX 110 Service Manual

Page 1

WARRANTY STATION

£0 TUNER PREAMPLIFIER M x 1 1 O

SERVICE MANUAL

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GENERAL DESCRIPTION ............... 1

TECHNICAL DESCRIPTION .............. 1

j INTRODUCTION ....................... 3

3 FM ALIGNMENT ....................... 4

MULTIPLEx ALIGNMENT ............... e

SCHEMATIC .......................... a

DIAL STRINGING ..................... I 11

PARTS LIST .......................... 12

-" SPECIFICATIONS ...................... 16

CHASSIS LAYoUT ..................... 18

OPERATING CURVES ................... 20

M AND x SERIES SCHEMATICS. ..... POCKET

.2 CHAMBERS _$T.
BINGHAMTON, N.Y.

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Page 2

MX 110 TUNER PREAMPLIFIER

GENERAL DESCRIPTION

The MX 110 combines in one unit an extremely
low-distortion preamplifier with a highly sensitive
FM multiplex stereo tuner. Every desirable
feature of a tuner and a preamplifier is included
in this design. Interstation noise suppression,
tuning indicator, FM multiplex indicator, indi-
vidual channel bass controls, individual channel
treble controls, electronic phase switch have all
been engineered into the MX 110. The INPUT
SELECTOR gives you a choice of six different
program sources. The MODE SELECTOR is a
newly developed control which makes it Very
easy to balance a stereo system. It is designed to
add left to right for monophonic operation, to
control the left to right stereo perspective or to
compare the left and right channels of a stereo
program. The loudness of the phono channels and
the auxiliary channel may be balanced to the

tuner loudness. These adjusting controls are
located on the top of the MX 110 behind the
front panel. By releasing the PANLOC buttons
on the front panel, you can slide the MX 110
out of its mounting until the second latch en-
gages. The top mounted LEVEL set controls are
now available.

The McIntosh designed PANLOC system is
the first professional installation technique to be
used on stereo instruments. The PANLOC sys-
tem gives you absolute ease of installation,
operation, and maintenance.

The McIntosh MX 110 is a beautifully engi-
neered control center for the finest stereo sound
systems. The extreme care in manufacturing, in
layout design and in thermal engineering prom-
ises the usual McIntosh extra values of reliability,
performance, and long life.

TECHNICAL DESCRIPTION

The radio-frequency amplifier of the MX 110 is
a cascode type circuit. The circuit is specially
designed to amplify weak signals with less noise
and distortion. By carefully tuning this RF
amplifier during manufacturing and controlling
other circuit constants, spurious response rejec-
tion is improved. The high-frequency oscillator
mechanical layout is engineered for minimum
response to temperature variations. In fact the
combination of mechanical and electronic design
is so unusually good in this circuit that automatic
frequency control is not needed in the MX 110.
The mixer output is amplified by four inter-
mediate frequency amplifiers. The transformers
used in the IF. amplifiers are designed for max-
imum adjacent channel rejection, for electrical
stability, and for electrical and mechanical
resistance to shock and vibration.

The RF. and IF. circuits of the MX 110
are completely shielded and exceed the FCC
requirements for suppression of oscillator radia-
tion. Either a 300 ohm or 75 ohm antenna may
be used with the MX 110. A VHF television
antenna which is suitable for FM reception can
be connected to the MX 110.

In the MX 110, a new type of mechanical
tuning assembly gives smooth flywheel tuning.
By controlling the relations between mass and
mechanical resistance, and'dividing work loads in
the dial drive system, it becomes nearly impossi~
ble to detect any backlash. Yet the entire dial
drive is a model of mechanical stability. For
smooth, quiet action and extended life with
virtuallyno wear. a teflon lined dial pointer
carriage and nylon pulleys are used in the dial
cord assembly.