McIntosh MI-3 Brochure
Mclntosh
The aim of Mclntosh...
to give you the most performance, the most reliability, the most satisfaction, for the least investment.
MI3
The Mclntosh MI 3 is five laboratory instruments combined into one compact unit.
It is a professional oscilloscope, relative signal
strength indicator, calibrated FM deviation
meter, calibrated balance meter and phase
indicator. These instruments are used by FM
stations to determine the best possible performance for your listening enjoyment. The
Mclntosh MI 3 Maximum Performance Indicator makes it easy for you to attain professional broadcasting quality FM listening.
MI3
The MI 3 gives a visual reference showing you
how to eliminate multipath reception. Multipath is a reception, and antenna problem. Generally it is independent of tuner specifications
or performance. To overcome multipath reception it is necessary to orient the antenna for
minimum multipath reception. With multi-
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The display changes position and shape with
the program material present in your stereo
system. With a small amount of practice you
can interpret what the display means to your
listening enjoyment.
To show multipath, the horizontal display
voltage is obtained from the tuner discriminator output before de-emphasis. This voltage is
proportional to the frequency deviation of the
FM transmission. The maximum width of the
indicator screen is designed to equal approxi-
mately plus and minus 75 KC deviation of the
FM transmitter.
path reception eliminated your FM reception
has:
... minimum noise level
... absolute minimum distortion
... fullest stereo separation
... overload protection from strong signals.
With practice, good clean FM signals are
easy to identify. Before you start recording you
can tell which FM stations you receive with a
good clean FM signal. You know when a station is broadcasting a true stereo broadcast.
You know when you are getting the maximum
performance possible from your FM tuner.
Here is how it works
The Mclntosh MI 3 is a professional oscilloscope. The three inch oscilloscope displays the
electrical signals present in your stereo system.
The vertical display voltage is obtained
from the tuner automatic gain control circuit
at the input of the first limiter. This voltage is
proportional to the station's signal strength.
Even weak stations will produce adequate vertical voltage for display.
For audio displays the horizontal display
voltage is obtained from the right channel output of the preamplifier or power amplifier. The
vertical display voltage is obtained from the
left channel output of the preamplifier or
power amplifier. The resultant display shows
you the amount of stereo separation. It also
shows the amplitude of the signals present.
Mclntosh C 22...
The Preamplifier
you don't hear
Music through a C 22 does not change measurably. The departure from perfection in the
power out of the C 22 is less than one part in
25,000,000. Pure music means hours of listening enjoyment. Every musical passage,
loud or soft, is re-created accurately.
Care in manufacturing
You get performance excellence with a C 22.
Each C 22 passes 47 tests designed to prove
it is ready for you. Frequency response, harmonic distortion, hum, balance, equalization,
plus all functions are tested and re-tested.
Published specifications are minimum per-
formance standards backed by a money back
guarantee.
The 757 parts in a C 22 run well within
their performance margins. This gives you
longer trouble free performance. You get a
free three year service contract with all
Mclntosh products. Low noise tubes, metal
film wire wound resistors plus high specific re-
Each part used is chosen for maximum performance and maximum reliability.
In dimly lit rooms the illuminated front
panel is easy to use. A brightness switch
gives you control of the amount of light on
the front panel. Both the mode and input
selector positions are shown by an easy to
see moveable red dot.
Features:
Four high level inputs, Aux, Tape, Tuner 1
and Tuner 2 plus four low level inputs, Tape
Hd, Mic, Phono 1 and Phono 2 are provided.
There are tape input/output jacks located on
the front panel. A portable tape recorder can
be used with the front panel jacks. If you want
to record merely turn the switch to record, to
playback, switch to playback. No other pre-
amplifier offers this convenience. Five AC
outlets are provided, four switched, one unswitched.
Separate bass and treble controls are used,
each having 11 steps. Each step is 4 db in-
sistivity circuit boards achieve low noise per-
formance thought impossible a few years ago.
crease or decrease. Record compensation is
either RIAA or LP. A tape monitor switch al-
C22
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lows instant checking of recordings in prog-
ress. A rumble filter with a 50 cycle cutoff
eliminates any low frequency noise from a
record player, or can be used to eliminate any
acoustic feedback in the system. A high frequency
surface noise on old noisy records, or from
noisy stereo broadcasts.
Behind the panel controls:
There are two output level controls, left and
right, plus a combined L+R output. There
are left and right low frequency trim controls
that boost up to 6 db below 100 cycles. Tape
head equalization is continuously variable for
maximum performance from various tape
heads. A phase switch provides the last nec-
essary touch for stereo enjoyment.
filter
with a 5,000
cycle
cutoff
reduces
Less than .1% at 3 volts output.
20 to 20,000 cycles
Hum and Noise
High level inputs:
85 db below rated output
Low level inputs: Less than
1.5 microvolts at input terminals
Outputs
Main (2 jacks on each channel) :
2.5 V with rated output
Tape: 0.25 V with rated output
L+R: 1 V from generator
impedance of 25,000 ohms
Input Sensitivity and Impedance
Auxiliary, 0.25 volts, 250,000 ohms.
Tape, 0.25 volts, 250,000 ohms.
Tuner 1, Tuner 2.
0.25 volts, 250,000 ohms.
Phono 1 and Phono 2:
2 millivolts, 47,000 ohms.
Microphone: 2.5 millivolts, 1 megohm.
Tape Head: 2 millivolts, 1 megohm.
Tape Compare: 0.25 volts, 250,000 ohms.
C 22 Specifications:
Frequency Response
± 0.5 db from 20 to 20,000 cycles
Distortion
Less than 0.2% at 10 volts output,
20 to 20,000 cycles
Dimensions
16" W
including connectors
Weight
16 pounds, 25 pounds
in shipping carton
by
5
7/16"
H by 13" D
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