MX 11O
STEREO TUNER
PREAMPLIFIER
CONTENTS
MX 11O
GENERAL DESCRIPTION
1
TECHNICAL DESCRIPTION
1
FRONT PANEL FACILITIES
5
INSTALLATION
10
CONNECTING
AC Connections
AC Power Connection
Input Connections
Output Connections
Antenna Connections
10
10
10
11
12
12
OPERATING INSTRUCTIONS
Balancing a Stereo System
13
13
Adjusting Phase
Balancing Loudness Between
Program Sources
Adjusting the Balance Control After the
System has been Balanced
Adjusting for Special Effects
Listening to Monophonic FM Program
Listening to MPX Stereo
Listening to a Stereo Record
Listening to Monophonic Records
Listening to Tape Decks
Listening to Stereo Tape Machine
Operating Curves
GUARANTEE
OWNER'S
14
14
15
15
15
16
16
16
16
17
18
20
MANUAL
MX11O
MX110 TUNER PREAMPLIFIER
GENERAL DESCRIPTION
The MX110 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, individual channel
bass controls, individual channel treble controls, electronic phase switch have all been
engineered into the MX110. 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 loud-
ness. These adjusting controls are located on
the top of the MX110 behind the front panel.
By releasing the PANLOC buttons on the
front panel, you can slide the MX110 out of
its mounting until the second latch engages.
The top mounted LEVEL set controls are
now available.
The Mclntosh designed PANLOC system
is the first professional installation technique
to be used on stereo instruments. The
PANLOC system gives you absolute ease of
installation, operation, and maintenance.
The Mclntosh MX110 is a beautifully
engineered control center for the finest
stereo sound systems. The extreme care in
manufacturing, in layout design and in thermal engineering promises the usual Mclntosh
extra values of reliability, performance, and
long life.
TECHNICAL DESCRIPTION
The radio-frequency amplifier of the
MX110 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 rejection 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 MX110. The mixer output
is amplified by four flat-topped intermediate
frequency amplifiers. The transformers used
in the LF. amplifiers are designed for maximum adjacent channel rejection, for electrical stability, and for electrical and mechanical
resistance to shock and vibration.
The R.F. and I.F. circuits of the MX110 are
completely shielded and exceed the FCC
requirements for suppression of oscillator
radiation. Either a 300 ohm or 75 ohm antenna may be used with the MX110. A VHF
television antenna which is suitable for FM
reception can be connected to the MX110.
In the MX110, 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 impossible to detect any
backlash. Yet the entire dial drive is a model
of mechanical stability. For smooth, quiet
action and extended life with virtually no
wear, a teflon lined dial pointer carriage and
nylon pulleys are used in the dial cord assembly.
1
MULTIPLEX DECODER
The multiplex decoder uses a special
Mclntosh developed detecting circuit. One of
the advantages of this circuit is the elimination of the critical adjustments necessary
with commonly used matrixing methods. This
circuit detects the L+R sidebands and automatically matrixes the recovered information with the L+R main carrier signal. This
circuit then yields the left and the right
program with maximum separation.
A temperature stabilized 19KC amplifier
locks-in a highly stable push-pull synchronous oscillator. Apart from other advantages,
this method provides greatest noise immunity. Balanced detectors cancel 19KC and
38KC components in the output and insure
low distortion.
A three-section sharp cut off filter rejects
SCA interference and reduces susceptibility
to spurious signals.
The MX110 has an MPX stereo indicator
that lights when the dial pointer crosses a
station broadcasting MPX stereo. A unique
circuit using a transistor operates the MPX
stereo indicator. The transistor is controlled
by a differential detecting circuit that amplifies the 19KC pilot signal. This circuit automatically discriminates between the 19KC
signal and noise.
AUDIO
The MX110 audio amplifier consists of
three negative-feedback amplifying sections
in duplicate for the left and right stereo channels and a separate L+R monophonic amplifier. The first section in each channel is a
feedback preamplifier used to amplify and
compensate for the input signals coming
from phonograph pickups or tape heads.
Level set controls are connected into the output circuit of this preamplifier section when
the INPUT SELECTOR is switched to PHONO
1 or PHONO 2. These controls may be used
to maintain uniform loudness between phono
and tuner inputs. Skillful layout, grounding,
and shielding for low-hum pickup, metal film
resistors, low-noise tubes and extreme care
in manufacturing combine to reduce noise
and hum in the input amplifiers.
The second amplifier section in each channel is a cathode follower. The sharp cut-off
(18db per octave) rumble and high-frequency
filters are associated with this section. Inputlevel set controls for the auxiliary inputs are
associated with this section. All the level set
controls are conveniently accessible
The third amplifier section is a two stage
negative feedback amplifier. The variable
bass and treble controls are included in the
feedback loop to maintain the lowest possible
distortion. For example a wave meter analysis of the three amplifier sections of the
MX110 shows less than 1/10 of 1% distortion at 3 volts output. The MODE SELECTOR, balance controls and left and right outputs are associated with the third amplifier
section.
The L+R monophonic amplifying section
is a feedback summing amplifier. It supplies
monophonic output as well as L+R output.
POWER SUPPLY
The power supply of the MX110 has received very special design attention. Three
separate rectifier circuits are used.
First, a full-wave rectifier supplies D.C. to
the heaters of all audio stages.
A second bridge rectifier supplies D.C. to
the anodes of the audio stages.
Then a third full-wave rectifier supplies
2
D.C. to the tuner stages.
This elaborate power supply design insures the lowest possible background hum
level and also the maximum stability. In
addition to this careful work the power transformer uses special magnetic shielding to
minimize possible hum pickup in the MX110
as well as in any other equipment used with it.
MECHANICAL SPECIFICATIONS
Dimensions
Chassis: 16 inches wide; 57/16 inches high;
13 inches deep including connectors.
Front Panel: 16 inches wide; 57/16 inches high.
Knob Clearance: 1½ inches.
Finish
Anodized gold and black (front panel).
Installation
Convenient, professional PANLOC.
Weight
Chassis: 27½ pounds.
Shipping Weight: 36 pounds.
TUNER SPECIFICATIONS
Sensitivity
Better than 2.5 microvolts at 100% modulation.
Frequency Response
Within ± 1db 20 to 20,000 cycles. (Including
75 microseconds deemphasis.)
R.F. Amplifier
Cascode.
LF. Amplifiers
Four.
Hum
Greater than 70db or more below 100%
mod. (Audio tubes have D.C. on the filaments.)
Limiters
Two.
Drift
Less than 25 KC.
LF. Bandwidth
200KC flat top.
Ant. Input Impedance
300 balanced, 75 ohms unbalanced.
LF. Transformers
Mechanically captive.
Radiation
Substantially below F.C.C. requirements.
Muting
LF. injected.
Tuning Indicator
Tuning is indicated by an electron ray tube.
Distortion
Less than 0.6% distortion at 100% modulation, ± 75KC deviation above 2.5 microvolts at antenna.
MULTIPLEX DECODER SPECIFICATIONS
MPX Decoder
Hum Level: Better than 60db below 100%
stereo modulation.
Distortion: Less than 0.3% (Multiplex Decoder only).
Channel Separation: Better than 30db at
1000 cps.
Suppression of Pilot (19KC), and Carrier
(38KC): Greater than 40db below 100%
modulation.
Front Panel Stereo Indicator Light: Activated by 19KC pilot carrier only.
AUDIO SPECIFICATIONS
Inputs
Total 5 each channel:
AUX.;
PHONO 1 MAG. or XTAL;
PHONO 2 MAG.;
TAPE HEAD;
TAPE MONITOR.
Outputs
Main Stereo Outputs, 1 Tape Stereo Output,
1 L+R Output.
AC AUX Outlets
1 unswitched, 2 switched.
3
Controls
Input Selector: Total 6 positions: AUX,
MPX, FM, PHONO 1, PHONO 2, TAPE
HEADS.
Mode Selector: Total 7 positions: L TO L&R,
R TO L&R, STEREO REV., STEREO, MONO,
L+R TO L, L+R TO R.
Tone: Dual treble and bass negative-feedback controls with slip clutch for independent adjustment of each channel. Bass
Boost: 15db at 50 cycles. Bass Cut: 18db
at 50 cycles. Treble Boost: 15db at 10,000
cycles. Treble Cut: 15db at 10,000 cycles.
Balance: Turn to right to emphasize the
right channel. Turn to the left to emphasize
the left channel.
Phase: 2 positions: NORMAL or REVERSED:
Changing phase does not increase distor-
tion. H.F. Cutoff Filter: 2 positions: Flat, or
5KC cutoff. (20db per octave.) L.F. Cutoff
Filter: 2 positions: Flat, or 50 cycles cutoff.
(20db per octave.)
Loudness: Fletcher Munson compensation.
Tape Monitor: 2 positions: IN and OUT. For
comparison of recorded tape with program
source after recording.
Tuning: Flywheel tuning—no backlash.
Muting: 2 positions: IN or OUT for interstation noise suppression.
Level Set: Three left and three right controls.
2 for AUX, 2 for PHONO 1, and 2 for
PHONO 2. These controls are located back
of the front panel on the top of the MX110.
AC Power—Concentric with BALANCE control: ON-OFF.
ELECTRICAL SPECIFICATIONS
Frequency Response
±½db 20 to 20,000 cycles.
TAPE HEAD: 3 millivolts at 220K.
TAPE MONITOR: 0.3 volt at 100K.
Distortion
Less than 0.2% at rated output.
Outputs
MAIN: 3 volts 2 in parallel each channel.
L+R: 3 volts.
Hum and Noise
High-level inputs: 80db below rated output.
Low-level inputs: less than 3 microvolts at
input terminals.
Input Sensitivity
AUX: 0.3 volt at 200K.
PHONO 1:3 millivolts at 47K.
PHONO 2: 3 millivolts at 47K.
TAPE: From FM at 100% modulation 0.9
volt from PHONO when cartridge output
is 9.0 millivolts—0.9 volt; with rated input
—0.3 volt.
POWER REQUIREMENTS: 105-125 volts AC
50/60 cycles; 75 watts.
FUSE: 1 amp. Slo-Blo.
TUBE COMPLEMENT
1
1
1
1
1
1
1
1
1
1
1
4
6DS4
R.F. -1 amplifier (nuvistor)
12AT7
R.F.-2 mixer
6AB4
Oscillator
6AU6
IF-1
6AU6
IF-2
6AU6
lF-3/Limiter 1
6CS6
IF-4/Limiter2
12AT7
Muting/L+R Amplifier
6HU6/EM87 Tuning Indicator
6D10
FM AUDIO/Left and Right
1st Audio Amplifier
6U8
MPX Amplifier and 19KC
Separator/Indicator control
1
1
1
1
12AU7
12AX7
12AX7
12AX7
1 6U8
1 6U8
2
1
Diodes
Diode
1
4
2
Diode
Diodes
Diodes
MPX 38KC Oscillator
Phono Preamplifier Left
Phono Preamplifier Right
Left and Right 2nd Audio
Amplifier
Left 3rd Audio Amplifier
Right 3rd Audio Amplifier
Discriminator
Muting and Tuning Eye
Detectors
AGC Clamp
Balanced MPX Detectors
Balanced Det. for Indicator
Light
Silicon
Diodes
1 MA113
4
2
DC Filament Supply
Transistor-Indicator Light
Switch
Selenium
Rectifiers
High and Low Voltage Supply
FRONT PANEL INFORMATION
Figure 1. MX110 Front Panel.
DIAL SCALES
The MX110 has two scales. The 88 to 108
scale is marked in megacycles. The 0 to 100
scale is the logging scale. The logging scale
can be used to accurately retune any station.
You may find it easier to keep a record of
your favorite stations by use of the logging
scale.
signal while rejecting noise pulses of equal
intensity. For listening to MPX stereo, refer to
OPERATING INSTRUCTIONS on page 00.
The tuning indicator off tune.
INDICATORS
The MX110 has two indicators. They are
just below each end of the logging scale. On
the right end is the MPX STEREO indicator.
On the left end is the tuning indicator.
Figure 2. MPX Stereo Indicator.
The MPX STEREO indicator will light up if
the dial pointer crosses a station broadcasting MPX stereo. A special circuit is used to
operate this panel indicator. This circuit
automatically detects the 19KC MPX stereo
The tuning indicator on tune.
Figure 3. Tuning Indicator.
The tuning indicator uses the movement
of two electron beams inside a vacuum tube
to show when a station is precisely tuned.
The beams move toward each other as the
station comes into tune. The station is precisely tuned when the beams come closest
together. The action of this indicator is substantially independent of the signal strength
of the station. Only the very weakest signals
will not close the beams.
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the output jack of the MX110. To properly
operate the MX 110, consult the section
titled OPERATING INSTRUCTIONS on page
13,
VOLUME
Figure 4. VOLUME Control.
The VOLUME control is the large knob
located to the left side of the dial face. The
volume control adjusts the loudness of both
stereo channels and also the L+R monophonic channel.
INPUT SELECTOR
4. PHONO 1—The PHONO 1 position of the
INPUT SELECTOR connects the jacks on the
back panel marked PH-1 MAG. and PH-1
XTAL through the MX110. Any stereophonic
or monophonic magnetic phono cartridge
plugged into the PH-1 MAG. jacks is fed
through the MX110. Any constant amplitude cartridge such as a crystal or ceramic
device plugged into the PH-1 XTAL jacks is
fed through the MX110. To properly connect
and operate the MX110 for use with phono
cartridges, see the sections titled CONNECTING on page 11 and OPERATING
INSTRUCTIONS on page 13.
5. PHONO 2—The PHONO 2 position of the
INPUT SELECTOR connects the jacks on the
back panel marked PH-2 through the MX110.
Any magnetic phono cartridge plugged into
the PH-2 jacks is fed through the MX110. To
properly connect and operate the MX110 for
use with phono cartridges, see the sections
titled CONNECTING on page 11 and OPERATING INSTRUCTIONS on page 13 .
Figure 5. INPUT SELECTOR.
1. AUX—The AUX position of the INPUT
SELECTOR connects the back panel jacks
marked AUX through the MX110. Use these
jacks to connect any high level program
source through the MX 110. Connections are
made following the instructions on page 11 in
the section titled CONNECTING. Operating
procedure is on page 13 in the section
titled OPERATING INSTRUCTIONS.
2. MPX—The MPX position of the INPUT
SELECTOR connects the multiplex decoder
to the output jacks of the MX110. Listen to
MPX stereo broadcasts in this position. To
properly connect and operate the MX110,
consult the sections titled CONNECTING on
page 11 and OPERATING INSTRUCTIONS
on page 13.
3. FM—The FM position of the INPUT SELECTOR connects FM monophonic programs to
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6. TAPE HD—The TAPE HD position of the
INPUT SELECTOR connects the jacks on the
back panel marked TAPE HEAD through the
MX110. A tape deck that does not contain
its own playback preamplifier is connected to
the MX110 through this position. To properly
connect and operate the MX110 for use with
tape decks, consult the sections titled CONNECTING on page 11 and OPERATING INSTRUCTIONS on page 13.
MODE SELECTOR
1. L TO L&R—The MODE SELECTOR in the
L TO L&R position connects the left input to
both amplifiers and both loudspeakers.
2. R TO L&R—The MODE SELECTOR in the
R TO L&R position connects the right input to
both amplifiers and both loudspeakers.
3. STEREO REV-The MODE SELECTOR in
the STEREO REV position connects the left
input to the right loudspeaker and right input
to the left loudspeaker.
pendently. Turning clockwise increases bass
loudness. Turning them counterclockwise
decreases bass loudness.
TREBLE
Figure 6. MODE SELECTOR.
4. STEREO—The MODE SELECTOR in the
STEREO position connects the left input to
the left loudspeaker and the right input to
the right loudspeaker. This is the normal
stereo position.
5. MONO—The MODE SELECTOR in the
MONO position adds the left input to the
right input and connects the L+R program
to both amplifiers and both loudspeakers.
6. L+R TO L—The MODE SELECTOR in the
L+R TO L position adds the left input to the
right input and connects the L+R program to
the left loudspeaker only.
7. L+R TO R-The MODE SELECTOR in the
L+R TO R position adds left input to the right
input and connects the L+R program to the
right loudspeaker only.
Figures. TREBLE Control.
The TREBLE control is a dual control. The
two parts are concentric. The center or small
knob controls the treble loudness in the left
channel. The outer ring controls the treble
loudness in the right channel. The two knobs
are friction coupled. This permits them to be
adjusted together or independently. Turning
clockwise increases the treble loudness.
Turning counterclockwise decreases treble
loudness.
MUTING
BASS
Figure 9. MUTING Control.
Figure 7. BASS Control.
The BASS control is a dual control. The
two parts of the control are concentric. The
center or small knob controls the bass loudness in the left channel. The outer ring controls the bass loudness in the right channel.
The two knobs are friction coupled, this permits them to be adjusted together or inde-
Muting suppresses the background noise
and hiss normally heard between stations.
With the control in the IN position the muting
is turned on. Weak stations that may not
override noise and interference are also
suppressed by the muting.
In the OUT position, the muting is turned
off. This allows conventional FM tuning with
the noise and interference present. Use this
position to tune weak or noisy stations.
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FILTERS
Figure 10. LF Rumble Filter Switch.
Low frequency noise below 50 cps is
reduced by pushing the LF rumble filter
switch to the IN position. Low frequency
acoustically coupled feedback is also reduced by this switch.
POWER OFF or left position (counterclockwise).
On the back panel of the MX110 there are
three A.C. OUTLETS. Two of these are black
and the other is red. The power to the black
outlets is controlled by the POWER switch.
The RED outlet is used for power to a turntable or a record changer. The turntable or
record changer drive system is protected by
this arrangement. It is necessary to turn off
the turntable or record changer with its own
control switch. The two black outlets and the
red outlet are not fused. Maximum rating for
these outlets is 350 watts total.
The BALANCE control balances the MX110
for unequal program sources. Turning the
control to the left accents the left channel by
reducing the right channel output. Turning
the control to the right accents the right
channel by reducing the left channel output.
LOUD
Figure 11. HF Filter Switch.
Surface noise above 5000 cycles is reduced when reproducing old, badly worn
recordings by pushing the HF filter switch to
the IN position.
POWER BALANCE
Figure 12. BALANCE Control.
The POWER ON-OFF switch is the center
or small knob of this dual control. The MX 110
is off when the POWER switch is turned to the
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Figure 13. LOUD Compensation Switch.
When you turn down the volume, the
music will seem to lose much of its bass and
some of its treble. This effect is due to the
sensitivity characteristic of human hearing.
The response of the human ear to bass and
treble pitch decreases more rapidly than
its response to notes centered in the midtonal range. The LOUD control automatically
provides the correct amount of bass and
treble boost required to compensate for this
change in response of the human ear at lowloudness levels. When the "LOUD" switch is
moved to the IN position, it converts the
volume control to a loudness compensated
control. Use the LOUD IN to listen at low
volume and still hear full-frequency range.
TAPE MONITOR
Figure 14 TAPE MONITOR Switch.
The TAPE MONITOR switch compares the
recorded tape with the program source.
When the TAPE MONITOR switch is in the
OUT position, the program source is heard
from the loudspeakers. When the TAPE
MONITOR switch is in the IN position, the
recorded tape is heard from the loudspeakers. Jacks marked TAPE MONITOR are
located on the back panel. Plug a signal into
these jacks from a tape machine which has a
third head and a preamplifier for it. IMPORTANT: When the TAPE MONITOR switch is
operated in the IN position, signal from any
other source will not be heard from the loudspeakers. When not in use, make sure the
switch is in the OUT position.
PHASE
Figure 15. PHASE Switch.
The PHASE switch corrects for loudspeaker or program phasing. Placing this
switch in the 180° position reverses phase in
the left channel.
LEVEL SET CONTROLS
The MX110 LEVEL SET controls (see
figure 16 compensate for the difference in
output level from various program sources.
The output level of the FM tuner, for example,
is higher than the output of a magnetic pickup. When you switch from one program
source to another, the level will vary to an
annoying degree. The level controls can be
set so that the output levels of all program
sources are equal. The MX110 LEVEL SET
controls are located on top of the MX110
chassis behind the front panel.
9
INSTALLATION
The MX 110 can be installed in conventional
furniture cabinets, custom built installations
or professional relay racks. If the unit is to be
placed on a shelf or table-top, it is recommended that it be housed in a Mclntosh
cabinet. Install the MX110 from the front of
the cabinet, not from the rear.
To support the weight of the MX110, the
wood panel used to mount it should be at
least ¼ inch thick.
The MX 110 installation should allow l3½
inches behind the front panel which includes
1½ inches for connectors. The desirable
width and height of the installation are 16
inches and a minimum of 5½ inches, respectively, so that sufficient space is allowed
for the circulation of air. These are inside
dimensions. The front panel mounting space
width and height are 16 inches and 53/8
inches, respectively. Allow at least 1½ inches
for knob clearance in a custom built installation.
CONNECTING
AC CONNECTIONS
There are three AC outlets on the rear
panel of the MX110. (See Figure 17.1 These
receptacles have a maximum rating of 350
watts total. The power to the two black
receptacles is controlled by the POWER
switch on the front panel. The red receptacle
is not switched. The red receptacle is used
for powering a turntable or record changer.
The receptacle is not switched so that the
turntable power will not be turned off while
the turntable idler wheel
engaged. The
turntable is protected by this arrangement
because it is necessary to turn off the turntable with its own control switch so that no
damage will result to the drive system.
AC POWER
Plug the AC power cord in 105 volt to 125
volt, 50 to 60 cycle power line. The power
used by the MX110 is 75 watts.
Figure 17. AC Connections.
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INPUT CONNECTIONS
The MX110 provides six separate program inputs controlled by the INPUT SELECTOR switch. One input for tape monitor or
tape comparison is controlled by the TAPE
MONITOR switch.
The input program connections should be
made in accordance with Table 1.
Figure 18. MX110 Input Connections (Back Panel).
If a cartridge requires less than 47,000
ohms load impedance, a resistor can be
added across the terminals of the cartridge
to achieve the correct termination. The
following chart may be used as a guide:
Desired Impedance
47,000 ohms (47K)
37,000 ohms (37K)
27,000 ohms (27K)
15,000 ohms (15K)
6,800 ohms (6.8K)
Resistor Across Input
No Resistor
180,000 ohms (180K)
62,000 ohms (62K)
22,000ohrns (22K)
8,200 ohms (8.2K)
Table 1. Input Connections
CONNECTION
FUNCTION
INPUT
SENSITIVITY
INPUT
IMPEDANCE
TAPE MONITOR
Tape input operates with tape machines containing their own
playback preamplifier.
0.3 volts
100,000 ohms
(100K)
AUX
The auxiliary input accepts any auxiliary service requiring flat
frequency response, such as a T.V. set, etc.
0.3 volts
200,000 ohms
(200K)
TAPE HEAD
This jack is used with a tape deck that does not contain its own
2.5 millivolts
playback preamplifier.
(25/1000 of 1 volt)
220,000 ohms
(220K)
PH-1 MAG
& PH-2 MAG.
These jacks are to be used with magnetic cartridges.
3 millivolts
(3/1000 of 1 volt)
47,000 ohms
(47K)
PH-1 XTAL
These jacks are to be used with a constant amplitude cartridge
such as a crystal, ceramic, or frequency-modulated device.
0.1 volts
220 mmf in
series with 56K
11
OUTPUT CONNECTIONS
There are three sets of outputs on the left
half of the back panel. (See Figure 19.) One
pair is marked MAIN. The second pair is
marked TAPE. The third is a single jack
marked L+R OUTPUT.
The MAIN output connects to power
amplifiers (Figure 19). The TAPE output
feeds a tape recorder.
The MAIN jacks are fed from cathode
followers. Longer cables than are normally
supplied can be connected between the
MX110 and the amplifiers. The length of the
cable is limited by the capacity of the cable.
The total capacity must not exceed 1000
mmf. For instance: cables with a capacity
of 25 mmf per foot may be 40 feet long; 13.5
mmf per foot cable may be 75 feet long. The
input impedance of the amplifiers should be
100,000 ohms or greater.
The TAPE output is fed from a cathode
follower. The program material fed out of the
TAPE output is not affected by these front
panel controls: VOLUME control, BASS controls, LF and HF filter switches, BALANCE
control, LOUD switch, TAPE MONITOR switch,
PHASE switch, TREBLE controls, and MODE
SELECTOR switch.
The program material fed out of the
TAPE output is affected by these front
panel controls: INPUT SELECTOR switch,
and in the FM or MPX positions of the INPUT
SELECTOR, the MUTING switch and TUNING
control.
The input impedance of the tape recorder
should be 100,000 ohms or greater.
A jack marked L+R OUTPUT is located
below the GND screw.
A monophonic signal can be distributed to
other rooms by connecting another power
amplifier to the jack marked L+R. The cable
connecting this output to the amplifier
should not have a capacity of more than
1000 mmf. The input impedance of the
power amplifier connecting to this output
should not be less than 150,000ohms(150K).
Figure 19. Output Connections
ANTENNA CONNECTIONS
Satisfactory MPX stereo requires about
10 times as much signal from the antenna.
Monophonic installations that are satisfactory on an indoor antenna may require
the use of an outdoor antenna for equivalent
results.
With the MX110 one of the three antenna
systems can be used: (1) the indoor dipole
supplied with the MX110, (2) an outdoor
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FM antenna, or 3 a VHF-TV antenna. In
fringe areas best results will probably be
obtained with the use of an outdoor FM
antenna. In many areas the indoor dipole
antenna may be satisfactory. The use of a
VHF-TV antenna is also effective in many
installations. Make a choice after consulting
the book on antennas titled "Themes and
Variations" included with MX110.
OUTDOOR ANTENNA
An outdoor antenna is recommended for
optimum performance in all areas. In fringe
(outlying) areas, best results will be obtained
with a highly directional FM antenna used in
conjunction with a rotator. Rotate the antenna until the best reception is obtained.
Connect the 300 ohm antenna to the terminal screws marked FM ANT as in Figure 20.
INDOOR DIPOLE ANTENNA
The flexible folded dipole antenna (300
ohm) supplied with the MX110 is for indoor
use in urban or high intensity signal areas.
The flexibility of the thin flat wire assembly
permits it to be placed under a rug, tacked
behind the hi-fi equipment enclosure . . . or,
placed in any other convenient location. In
some cases, it may be necessary to "position" the antenna for best signal reception.
This should be done before it is permanently
located or tacked down.
To position the dipole for best results, the
MX110 must be operating. The following
procedure may be followed: Connect the two
leads from the dipole to the terminals marked
FM ANT on the rear of the chassis of the
MX110, see Figure 20.
IMPORTANT:
BEFORE TURNING THE MX110 ON,
CHECK TO SEE THAT ALL TUBES ARE
FIRMLY SEATED IN THEIR SOCKETS,
AND THAT ALL PLUGS ARE CORRECTLY
AND FIRMLY INSERTED.
Turn the POWER switch ON. Then the
MODE SELECTOR to STEREO. Place the
MUTING control in the OUT position. Open
the dipole to a full "T" and tune the MX110
to a fairly weak station. Rotate and move the
dipole about until the best reception is obtained. The dipole is now in the best position
for maximum signal reception for this station. This is not a critical position; therefore
you may permanently install the antenna in a
position which most closely conforms to it.
Keep the dipole away from metal surfaces, metal doorways, etc., as they usually
interfere with its efficiency.
CONNECTING A 75 OHM COAXIAL
ANTENNA LEAD
Figure 21. Connections for a 75 ohm antenna
Figure 20. Connection for 300 ohm antenna
An unbalanced 75 ohm antenna can be
connected to the MX110 with coaxial cable.
Connect the center conductor to the left FM
ANT screw and the shield to the grounding
screw next to the antenna screw as in Figure
21. The Mclntosh designed balun matches
the 75 ohm input to the tuner for optimum
performance.
OPERATING INSTRUCTIONS
BALANCING A STEREO SYSTEM
The performance and enjoyment of a
stereo system is greatly increased when
the system is properly balanced. There are
two factors that require balancing. One is
unequal program loudness in each channel.
The knob marked BALANCE on the MX110
13
is used to balance unequal program loudness. Balancing program for equal loudness
is explained under ADJUSTING BALANCE
CONTROL TO CORRECT PROGRAM MATERIAL.
The other factor that requires balancing
is system balance. The balance of the stereo
system is affected by many things including
room acoustics, furniture placement, room
shape, small differences in loudspeakers,
etc. Balancing the system is done by adjusting the controls on the power amplifiers.
To begin balancing the system, check to
see that the controls on the amplifier are
properly set. If the amplifier is a Mclntosh
MC225, set the input switch to STEREO. Turn
both input level controls to the black dot at
the 12 o'clock position of the control.
If the amplifier is a Mclntosh MC240 or
MC275 check to see that the cables from the
MX110 are plugged into the STEREO INPUT
jacks. Then set the lever switch to STEREO.
Turn the BALANCE control to the 0 mark at
the 12 o'clock position of the control. The
amplifiers are now ready for the rest of the
steps to balancing the system.
1. Play a familiar recording on the record
player.
2. Push the two PANLOC buttons to release the MX110 from the mounting shelf.
Pull the MX110 toward you until the latch
locks engage. Turn all the INPUT LEVEL
ADJUST controls full on (clockwise).
3. Turn the INPUT SELECTOR to the
PHONO position into which the record player
is connected.
4. Turn the BASS controls and TREBLE
controls so that the knob indicator is centered between the panel markings L and R.
5. Turn the BALANCE control to the center
or 12 o'clock position.
6. Place the LOUD switch in the OUT
position.
7. Place the TAPE MONITOR switch in the
OUT position.
8. Place the PHASE switch in the 0°
position.
9. Place the LF rumble filter switch in the
OUT position.
14
10. Place the HF cutoff filter switch in the
OUT position.
11. Turn the MODE SELECTOR to the L+R
TO L position.
12. While the program is playing, alternate
the MODE SELECTOR between the L+R TO
R and the L+R TO L position. On amplifiers
such as the MC225, adjust the correct gain
control until the loudspeakers are of equal
loudness. On the MC240 or the MC275, turn
the balance control until the loudspeakers
are of equal loudness.
The stereo system is now balanced. It will
remain balanced through all modes of operation. Leave the MX110 extended on its
PANLOC stops for the next series of adjustments.
ADJUSTING
PHASE
1. Set the MODE SELECTOR to STEREO.
2. Turn the BASS controls and TREBLE
controls to straight up position so that the
dial indicator centers between the panel
markings • L and ° R.
Stand approximately 10 feet in front of
and midway between the loudspeakers. The
source of sound should appear to be directly
in front of you. Alternate the PHASE switch
between 0° and 180°. If the sound is not
directly in front of you in the 0° position,
reverse the leads to one loudspeaker. The
PHASE control is used to correct phase in the
source material whenever necessary.
BALANCING LOUDNESS BETWEEN
PROGRAM SOURCES
The MX110 has set level controls in the
AUXILIARY, PHONO 1 and PHONO 2 inputs.
These adjustments allow you to make any
program material connected to the auxiliary
and phono inputs the same loudness as the
tuner. To make this adjustment proceed as
follows:
1. Turn the MODE SELECTOR to MONO
(L+R).
2. Turn the INPUT SELECTOR to FM.
Adjust the VOLUME control to a comfortable
listening level.
3. While the record is playing, turn the
MODE SELECTOR to the L+R to L position.
4. Now switch the INPUT SELECTOR between FM and PHONO. If the record is louder
than the FM turn the INPUT LEVEL, ADJUST
CONTROL marked PHONO L down (counterclockwise). When the loudness of FM and the
record are equal, the left channel level is
correct.
5. Turn the MODE SELECTOR to L+R to R.
6. Again switch the INPUT SELECTOR
between FM and PHONO. If the record is
louder than the FM, turn the INPUT LEVEL
ADJUST CONTROL marked PHONO R down
(counterclockwise). When FM and the record
are equal, the right channel is correct.
Use these same steps to adjust the AUX
input loudness. Remember to compare the
loudness to the FM only. The FM does not
have controls for loudness adjustment.
ADJUSTING BALANCE CONTROL AFTER
THE SYSTEM HAS BEEN BALANCED
When these instructions have been completed, the overall system is balanced and in
phase; ready to deliver maximum pleasure
and enjoyment.
You may hear differences in balance from
one record to another or from one tape to
another. Some records or tapes may be
recorded with slight differences between
channels. The differences can be corrected
with the BALANCE control on the front panel.
If the difference is heard on every record,
then the cartridge may have a very small
difference in output.
ADJUSTING FOR SPECIAL EFFECTS
HF Cutoff Filter. If you wish to reproduce
old, badly worn records, you can minimize
the surface noise by switching the HF cutoff
filter to the IN position. (See section entitled "Front Panel Facilities," page 5.)
LF Rumble Filter. If you are using a turntable or changer which has low-frequency
rumble noise, you may reduce it by pushing
the LF rumble filter switch to the IN position.
Bass Controls and Treble Controls. The
tone balance which you hear when listening
to an orchestra is affected by the conductor's
instructions to his musicians, the acoustical
environment m which you are listening, and
your own subjective hearing interpretation.
Considering these conditions, it is easy to see
why tone balance controls play a major role in
correcting for the following factors:
1. Each person's subjective idea of tone
balance.
2. Loudspeaker frequency response characteristics.
3. Loudspeaker placement in the listening room.
4. The conductor's idea of tone balance
at the time the recording was made.
5. The microphone frequency response
characteristics.
6. The recording process influences.
These factors can be considered as environmental influences. The BASS controls
and TREBLE controls are designed to provide
a degree of compensation for effects of
environment. Listen to your system with
each control set with the indicators centered
between the panel markings • L and ° R. If
you wish to reduce treble in relation to bass,
turn the TREBLE controls counterclockwise
until the tone balance sounds correct to you.
These controls will modify tone balance without introducing any undesirable effects. Do
not be surprised if you find your preference
in tone changing from time to time.
Loudness. Due to a selective shift in sensitivity of human hearing, music reproduced
at very low volume loses its bass and treble.
The LOUD switch on the MX110 changes
the VOLUME control to a loudness compensated control to correct for this effect.
When you wish to listen to music at a greatly
reduced loudness level and yet hear bass and
treble, set the LOUD switch to the IN position.
Phase. If the stereo sound seems to come
from either side of the room instead of being
distributed between the loudspeakers, adjust
the PHASE control to 180°. This listening
effect is due to reproducing sound that is
out of phase from one channel to the other.
You will find some records differ from others
in this respect and that some tapes differ
from records.
LISTENING TO A MONOPHONIC
FM PROGRAM
1. Turn the INPUT SELECTOR to FM.
2. Turn the MODE SELECTOR to MONO
15
(L+R)
3. Place the PHASE switch in the 0°
position.
4. Place the HF cutoff filter switch in the
OUT position. (See page 15 ADJUSTING FOR
SPECIAL EFFECTS.)
5. Place the LF rumble filter switch in the
OUT position. (See page 15 ADJUSTING
FOR SPECIAL EFFECTS.)
6. Place the LOUD switch in the OUT position. (See page 15 ADJUSTING FOR SPECIAL EFFECTS.)
7. Turn the BASS controls and TREBLE
controls so that the indicator is centered
between the panel markings • L and ° R.
(See page 15 BASS AND TREBLE CONTROLS.)
8. Place the MUTING switch in the IN
position.
9. Adjust the VOLUME control to the
desired volume.
After a warm up of about 30 seconds, turn
the tuning knob to find the station of your
choice.
While tuning the MX110 you may notice
that the tuning indicator will show a station
yet no program is heard from the speakers.
The muting circuit in the tuner is rejecting the
station because there is objectionable noise
with the weak signal from the station. Push
the MUTING switch to the OUT position and
the station will be heard. Most programs that
can be tuned in this manner are of poor
quality due to interfering noise.
LISTENING TO MPX STEREO
If you are tuning the MX110 and the red
MPX indicating light comes on, this indicates
a multiplex broadcast. To listen to this program:
1. Turn the INPUT SELECTOR to MPX.
2. Turn the MODE SELECTOR to STEREO.
LISTENING TO A STEREO RECORD
To listen to stereo records, proceed as
follows:
1. Turn the INPUT SELECTOR to PHONO
1 or PHONO 2, whichever is connected to
the cartridge you wish to hear.
2. Set the MODE SELECTOR to STEREO.
3. Set the PHASE switch to 0°.
4. Set the HF cutoff filter to OUT. (See
page 15 ADJUSTING FOR SPECIAL EFFECTS.)
16
5. Place the LF rumble filter control in the
OUT position. (See page 15 ADJUSTING
FOR SPECIAL EFFECTS.)
6. Set the LOUD control to OUT. (See
page 15 ADJUSTING FOR SPECIAL EFFECTS.)
7. Set the BASS controls and TREBLE
controls so that the indicator is centered
between the panel markings • L and ° R.
(See page 15 BASS AND TREBLE CONTROLS.)
8. Adjust the VOLUME control to the
desired volume.
LISTENING TO MONOPHONIC RECORDS
To listen to monophonic records, proceed
as follows:
1. Turn the INPUT SELECTOR to PHONO
1 or PHONO 2 whichever is connected to the
cartridge you wish to hear.
2. Set the MODE SELECTOR to MONO
(L+R).
3. Set the PHASE switch to 0°.
4. Set the HF cutoff filter to OUT. (See
page 00 ADJUSTING FOR SPECIAL EFFECTS.)
5. Place the LF rumble filter control in the
OUT position. (See page 15 ADJUSTING
FOR SPECIAL EFFECTS.)
6. Set the LOUD control to OUT. (See page
00 ADJUSTING FOR SPECIAL EFFECTS.)
7. Set the BASS controls and TREBLE
controls so that the indicator is centered
between the panel markings • L and ° R.
(See page 15 BASS AND TREBLE CONTROLS.)
8. Adjust the VOLUME control to the
desired volume.
LISTENING TO TAPE DECKS
To listen to tape from a tape deck, proceed as follows:
1. Turn the INPUT SELECTOR to TAPE
HEAD.
2. Set the MODE SELECTOR to MONO
(L+R) or STEREO, depending on the program on the tape.
3. Set the PHASE switch to 0°.
4. Set the HF cutoff filter to OUT. (See
page 15 ADJUSTING FOR SPECIAL EFFECTS.)
5. Place the LF rumble filter control in
the OUT position. (See page 15 ADJUSTING
FOR SPECIAL EFFECTS.)
6. Set the LOUD control to OUT. (See page
15 ADJUSTING FOR SPECIAL EFFECTS.)
7. Set the BASS controls and TREBLE
controls so that the dial indicator is centered
between the panel markings • L and ° R.
8. Adjust the VOLUME control to the
desired volume.
7. Set the BASS control and TREBLE controls so that the dial indicator is centered
between the panel markings • L and ° R.
8. Adjust the VOLUME control to the desired volume.
LISTENING TO A STEREO TAPE MACHINE
If the TAPE MONITOR input is used proceed as follows:
1. Push the TAPE MONITOR switch to IN.
2. Set the MODE SELECTOR switch to
MONO (L+R).
3. Set the PHASE switch to 0°.
4. Set the HF cutoff filter to OUT. (See
page 15 ADJUSTING FOR SPECIAL EFFECTS.)
5. Place the LF rumble filter control in the
OUT position. (See page 15 ADJUSTING
FOR SPECIAL EFFECTS.)
6. Set the LOUD control to OUT. (See page
15 ADJUSTING FOR SPECIAL EFFECTS.)
7. Set the BASS controls and TREBLE
controls so that the dial indicator is centered
between the panel markings * L and ° R.
8. Adjust the VOLUME control to the
desired volume.
A stereo tape machine with its own playback preamplifiers should be plugged into
the AUX input or the TAPE MONITOR input
—not the TAPE HEAD input.
If the AUX input is used, proceed as
follows:
1. Turn the INPUT SELECTOR to AUX.
2. Set the MODE SELECTOR to MONO
(L+R) or STEREO depending on the program
on the tape.
3. Set the PHASE switch to 0°.
4. Set the HF cutoff filter to OUT. (See
page 00 ADJUSTING FOR SPECIAL EFFECTS.)
5. Place the LF rumble filter control in the
OUT position. (See page 15 ADJUSTING FOR
SPECIAL EFFECTS.)
6. Set the LOUD control to OUT. (See
page 00 ADJUSTING FOR SPECIAL EFFECTS.)
17
OPERATING
CURVES
EQUALIZATION CURVES
20
15
R E S P O N S E IN OB
10
5
0
-5
-10
-15
-20
20
1 KC
100
10 KC
20KC
FREQUENCY
Figure 22. Equalization Curves.
BASS AND TREBLE CONTROLS
20
RESPONSE
IN DB
10
0
-10
-20
20
100
1KC
FREQUENCY
Figure 23. Bass and Treble Controls.
18
10 KC
20 KC
LOW AND HIGH FREQUENCY FILTERS
0
-20
-30
-40
-50
20
I KC
100
10KC
20 KC
10 KC
20 KC
FREQUENCY
Figure 24 LF. Filter and H.F. Filter.
LOUDNESS CONTROL
20
15
10
RESPONSE IN DB
R E S P O N S E IN DB
-10
5
0
-5
-10
-15
-20
20
100
1 KC
FREQUENCY
Figure 25 Loudness Control.
19
Your MX110 will give you many years of pleasant and satisfactory performance. If you have any questions concerning the operation or maintenance of this tuner-preamplifier please contact:
Customer Service
Mclntosh Laboratory Inc.
2 Chambers Street
Binghamton, New York
Our telephone number is 723-5491.
The direct dial area code is 607.
GUARANTEE
Mclntosh Laboratory Incorporated guarantees this equipment to perform as advertised. We also guarantee the mechanical and
electrical workmanship and components of
this equipment to be free of defects for a
period of 90 days from date of purchase.
This guarantee does not extend to components damaged by improper use nor does it
extend to transportation to and from the
factory.
3-YEAR FACTORY SERVICE CONTRACT
An application for a FREE 3-YEAR FACTORY SERVICE CONTRACT is included in
the pocket in the back cover of this manual.
The FREE 3-YEAR FACTORY SERVICE CONTRACT will be issued by Mclntosh Laboratory
upon receipt of the completely filled out
application form. If the application is not
mailed to Mclntosh Laboratory, only the
services offered under the standard 90-day
guarantee will apply on this equipment.
TAKE ADVANTAGE OF 3 YEARS OF FREE
FACTORY SERVICE BY FILLING IN THE
APPLICATION NOW.
Design subject to change without notice.
20
LABORATORY INC.
2 CHAMBERS STREET, BINGHAMTON, N. Y.
Made in U S A
Phone-Area Code 607-723-5491
1M 038-025
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