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
loudness. 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.
The MX110
combines in one convenient instrument an FM Tuner, a Multiplex Decoder ana a
Stereo Preamplifier. You mount only this one unit, connect it to your power
amplifier and speakerss and you're ready to go.
The
electronic circuits in the preamplifier are so skillfully engineered that a
wave-form analusis at 3 volts output shows typically only 1/20th of 1%
distortion 20 cycles through 20,000 cycles. The stability of the tuner circuits
has been improved to the point that A.F.C. is no longer needed. Sensitivity is
also increased over previous models. The MX110 uses a newly developed indicator
which lights whenever the tuner is centred on a station broadcasting the 19KC
carrier for miltiplex stereo. The control circuit for the indicator respondes
only to the 19KC and is insensitive to noise.
The MX110
also uses the new, exclusive McIntosh PANLOC method installation. The PANLOC
system gives you absolute ease of installation, operation, and maintenance.
PANLOC is the first professional installation technique to be used on stereo
instruments.
The MX110 is
a model of convenience, careful planning and rigorous manufacturing methods.
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.
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.
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.
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 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.
TUNER
SPECIFICATIONS
Sensitivity: Better than 2.5 microvolts at 100%
modulation.
R.F.
Amplifier: Cascode.
LF.
Amplifiers: Four.
Limiters: Two.
LF.
Bandwidth: 200KC flat top.
LF.
Transformers: Mechanically captive.
Muting: LF. injected.
Tuning
Indicator: Tuning is indicated by an
electron ray tube.
Frequency
Response: Within ± 1db 20 to 20,000
cycles. (Including 75 microseconds deemphasis.)
Hum: Greater than 70db or more below 100% mod.
(Audio tubes have D.C. on the filaments.)
Drift: Less than 25 KC.
Ant. Input
Impedance: 300 balanced, 75 ohms
unbalanced.
Radiation: Substantially below F.C.C. requirements.
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.
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.
Distortion: Less than 0.2% at rated output.
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 HEAD
: 3 millivolts at 220K.
TAPE MONITOR
: 0.3 volt at 100K.
Outputs:
MAIN : 3 volts 2 in parallel each channel.
L+R : 3 volts.
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 6DS4 R.F.
-1 amplifier (nuvistor)
1 12AT7
R.F.-2 mixer
1 6AB4
Oscillator
1 6AU6 IF-1
1 6AU6 IF-2
1 6AU6
lF-3/Limiter 1
1 6CS6
IF-4/Limiter2
1 12AT7
Muting/L+R Amplifier
1 6HU6/EM87
Tuning Indicator
1 6D10 FM
AUDIO/Left and Right
1st Audio
Amplifier
1 6U8 MPX
Amplifier and 19KC
Separator/Indicator
control
1 12AU7 MPX
38KC Oscillator
1 12AX7
Phono Preamplifier Left
1 12AX7
Phono Preamplifier Right
1 12AX7 Left
and Right 2nd Audio Amplifier
1 6U8 Left
3rd Audio Amplifier
1 6U8 Right
3rd Audio Amplifier
2
DiodesDiscriminator
1
DiodeMuting and Tuning Eye Detectors
1 Diode AGC
Clamp
4 Diodes
Balanced MPX Detectors
2 Diodes
Balanced Det. for Indicator Light
2 Silicon
Diodes DC Filament Supply
1 MA113
Transistor-Indicator Light Switch
4 Selenium
Rectifiers High and Low Voltage Supply
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.
Weight
Chassis:
27½ pounds.
Shipping
Weight: 36 pounds.
Finish: Anodized gold and black (front panel).
Installation
Convenient, professional PANLOC.
