McIntosh MAC-4100 Brochure

MAC

4100

The MAC

4100

is

the most

Value Packed Receiver

in the world

The MAC

comes with walnut grained vinyl cabinet

4100

1. FIVE BAND PROGRAM EQUALIZER

Five separate controls allow great flexibility

when compensating for program deficiencies.

2. "LED" POWER OUTPUT INDICATORS

Two columns of seven yellow "LED" indicators

provide an indication of the amount of power be­ing fed to your speakers.

3. POWER GUARD INDICATOR AND
PROTECTION CIRCUIT

Two red "LED" power guard indicators indicate

when the power amplifier has reached full output.
At this point the power guard circuit begins to
control amplification dynamically so that you will

not hear the harsh distorted sound of square
wave clipping. In addition your speakers are pro­tected from burnout.

4. ELECTRONIC AUDIO SIGNAL SWITCHING

FET analog switches are used to give smooth swit-

ching transition from one input to another without

clicks and pops.

5. SUPER-TRACKING VOLUME CONTROL

The volume control is a precision stepped at-

tenuator which has left to right tracking accuracy
within 1 dB throughout its entire range. System
balance is maintained at all listening levels.

6. LESS THAN 0.05% TOTAL
HARMONIC DISTORTION

Harmonic distortion does not exceed 0.05% when
measured from the phono input to the speaker

output from 20 Hz to 20 kHz at all power levels

from 250 mW to full rated output.

7. TRUE VARIABLE LOUDNESS

COMPENSATION CONTROL

The loudness control operates independently of
the volume control and its contour is accurately

modeled after the Fletcher Munson family of
"equal loudness" curves.

8. DUAL TAPE MONITOR AND
TAPE COPY SWITCHES

Two tape recorders can record simultaneously

from the program being listened to or you may
record from one to the other without interfering
with the "Listen" program.

9. SPEAKER SWITCHES FOR
THREE SETS OF SPEAKERS

Three sets of loudspeakers may be used one at
a time, two together, or all three simultaneously.

10. SPEAKER PROTECTION CIRCUITS

Loudspeakers are protected from burnout by
the Power Guard circuit and also by other cir­cuits that instantaneously disconnect the
speakers in the event of the presence of DC on
the output.

11. PREAMP OUTPUT • POWER AMP
INPUT CONNECTIONS

Back panel connections provide the ability to
insert room equalizers, reverberation units or
other signal processing devices.

12. LOW NOISE ION-IMPLANTED J-FET OP-AMPS

New technology low noise operational
amplifiers give lower noise and greater band­width than conventional devices.

13. ELECTRONIC ACTIVE FILTER ELEMENTS

"Active filter" technology is used to generate

the equivalent of the inductors normally used in
equalizer filters. This eliminates the hum

pickup or inductance non linearity that often

occurs from conventional inductors.

14. MOS-FET FM FRONT END

Great signal sensitivity together with freedom
from strong signal overload is made possible
by using MOS Field Effect Transistors in the

FM RF circuits.

15. ULTRA STABLE LINEAR-PHASE
PIEZOELECTRIC FM IF FILTERS

The IF filters are permanently sealed and never

require adjustment. The IF response curve is

extremely selective because of its very steep
slope either side of center and yet it has a

linear phase characteristic.

16. AUTOMATIC FREQUENCY LOCK

Perfect FM tuning is assured by holding off the

tuning lock signal until manual tuning reaches
the center of the FM carrier.

17. WIDE RANGE SIGNAL STRENGTH METER

The signal strength meter pointer responds all

the way from 1 microvolt of antenna noise
pickup to over 50,000 microvolts of signal
strength. This allows accurate directional
antenna orientation.

18. FM TUNER SCOPE PLUG IN CONNECTIONS

An oscilloscope or maximum performance in­dicator may be connected easily to adjust a
directional antenna for minimum FM multipath
distortion.

19. FM MULTIPLEX THIRD GENERATION
PLL CIRCUIT

Tri-level electronic switching in the multiplex
decorder gives better separation, lower distor­tion, and superior SCA rejection. Contains tri­level logic for better separation. No inductors
required, minimizing drift; Integral lamp driving
capability to indicate presence of a 19 kc pilot
carrier; Excellent channel separation over the
entire audio frequency range; Extremely low
distortion; Low output impedance; Transient
free mono/stereo switching.

20. MULTIPLEX PILOT AND

CARRIER SUPPRESSION CIRCUIT

The 19 kHz pilot and 38 kHz carrier are removed
from the output thereby eliminating the

possibility of introducing these undesirable

signals to the tape recorder input.

21. "AUTO-ON" AC OUTLETS

Power to the entire stereo system can be con­trolled from either the front panel power switch
or the power switch on a system turntable.

22. SWITCHED AC OUTLETS

AC outlets are provided for accessory equip-

ment that turn on and off with your receiver.

23. "LED" FUNCTION INDICATORS

System status is indicated by long life "LED"

indicators.

24. TURN-ON TRANSIENT

ELIMINATION CIRCUITS

Speaker outputs are connected only after

power supplies and circuits have stabilized

eliminating turn on thumps or clicks.

TECHNICAL HIGHLIGHTS

Phono Amplifier

The phono amplifier uses a new high technology in­tegrated circuit operational amplifier. Its differential in­put stage has been optimized for low noise and low
distortion performance. Open loop gain of this in­tegrated circuit is 100,000. With high open loop gain a
large amount of negative feedback can be used around
the phono amplifier to further reduce noise and distor­tion. The feedback network also provides precision
RIAA frequency compensation. It uses 1% metal film
resistors and 5% poly film capacitors. To achieve low
noise performance it is essential that the feedback net­work be very low impedance. As a consequence, the

preamplifier must be capable of operating as a power
amplifier to drive this impedance. The actual power
output capability of this preamplifier stage is more
than 100 milliwatts, a great margin beyond that which

is required.

Input Selector Switching

Electronic input selector switching uses field effect
analog switches. The mechanical input selector simply
switches small amounts of DC which turn the FET
analog switches off or on. This design eliminates
degradation of frequency response and also
eliminates noise pickup from long signal paths

necessary with conventional mechanical switching. It

means, as well, that switch clicks and pops have been
eliminated.

Equalizer Amplifier

The equalizer amplifier is constructed with ion im-

planted junction field effect operational amplifiers.
These new devices amplify signals with a 6 dB better

signal to noise ratio than their bipolar counterparts.

Five other operational amplifiers are each arranged in

circuit configurations that are the equivalent of series

tuned circuits, one at each of the five center frequen-

cies. Each series tuned circuit is inserted via the con-

trol potentiometer in either the input circuit or feed-

back circuit of the FET op-amp thereby providing a

boost and cut capability of 12 dB for each band of fre-

quencies. The equalizer amplifier has a gain of 0 dB.

Power Guard

Amplifiers are capable of delivering large quantities of

power when they are driven to clipping. Clipping is

caused when the amplifier is asked to produce more

power output than it can deliver with low distortion. A

clipped amplifier can have more than 40% harmonic

distortion. The extra energy content of the clipped

signal will damage most loudspeakers, particularly the

delicate high frequency tweeters. A new Mclntosh ad-

vancement helps protect your speakers from this kind

of damage. The MAC 4100 has a built-in waveform com-

parator that compares the wave shape of the input

signal with the output signal. If the disparity between

the two signals exceeds 0.5% (equivalent to 0.5% total

harmonic distortion) a front panel signal illuminates in

red at the top of the power output indicators. With any

further increase in distortion the POWER GUARD cir-

cuit will operate. This circuit limits the input

dynamically so that the amplifier cannot be overdriven.

POWER GUARD eliminates amplifier output clipping.

POWER GUARD does not limit the dynamic range or

the power output of the power amplifier. Clipping oc-

curs when an amplifier runs out of power supply. Since

POWER GUARD does not begin to work until this point

is reached, the power capability of the amplifier is

never affected.

FM Section

The FM-IF consists of five integrated circuits and four

piezo electric filters. They combine to give a total gain
of over 140 dB. The signal is amplified over a million
times. The response curve has nearly linear phase
characteristics. The skirts of the response curve are
very steep. The maximum width is 170 kHz at 3 dB and
500 kHz at 60 dB. The response is symmetrical each
side of the center frequency. The filters are permanent­ly sealed and never require adjustment. They cannot
drift or vibrate out of adjustment. The exceptionally

high gain of the five integrated circuits assures hard

limiting at very low levels of input signal.

A "phase" or "Foster-Seeley" discriminator has been
designed to complement the integrated circuit IF sec­tion. The detection output of the discriminator is ex­tremely low in distortion.

FM Stereo Multiplex Section

The heart of the multiplex section is a new third

generation phase lock loop (PLL) stereo decoder in-

tegrated circuit (IC). This PLL IC incorporates two

special systems, an automatic variable separation con-

trol circuit to reduce background noise when receiving
weak stereo stations, and a tri-level digital waveform
generation which eliminates interference from SCA

signals and from the sidebands of adjacent channel

FM signals.
The variable separation control is operated from the IF

amplifier's signal strength detector system. A smooth

transition is provided from mono to stereo or visa versa

at weak signal levels to provide the optimum signal to

noise ratio and best stereo separation for the prevail-

ing signal conditions. The circuit operates only during
stereo reception, it switches automatically to
monaural if the 19 kHz pilot tone is absent.

In the PLL the internal oscillator operates at 228 kHz

locked to the 19 kHz pilot tone. The 228 kHz feeds a 3
stage Johnson counter via a binary divider to generate
a series of square waves. Suitably connected NAND
gates and exclusive OR gates produce the tri-level
drive waveform for the various demodulators in the cir­cuit. The usual square waveforms have been replaced

in the PLL and decoder sections by tri-level waveforms.
These tri-level forms contain no harmonics which are

multiples of 2 or 3. This eliminates frequency trans-

lation and detection of interference from the side-

bands of adjacent stations since the third harmonic of
the sub-carrier (114 kHz) is excluded and interference

from SCA broadcasts since the third harmonic of the

pilot tone (57 kHz) is excluded. Unwanted spurious

audible components and phase jitter in the PLL with

consequent intermodulation distortion are inherently

eliminated by this technique.

Additional advantages of the phase locked loop stereo

demodulation are the elimination of inductors to

minimize drift, integral lamp driving capability to in-

dicate the presence of the 19 kHz pilot carrier, ex-

cellent channel separation over the entire audio fre-

quency range, extremely low distortion, low output im-

pedance, and transient-free mono/stereo switching.

After multiplex detection, 19 kHz pilot and 38 kHz car-

rier suppression circuits are used to prevent tape

recorder interference.
The FM muting circuit is unusual. It operates both by

detecting ultrasonic noise and by sensing correct tun-

ing of the detector circuit. To 'un-mute' it is necessary

for the signal to have an adequate signal-to-noise ratio

and to be tuned to the center of the FM carrier. The

MUTING circuit can be activated or defeated by the
front panel muting pushbutton. The switching on and

off of the audio signal is done with FET analog switches.

MAC

4100

PERFORMANCE

LIMITS

Performance limits are the maximum deviation from
perfection permitted for-a Mclntosh instrument. We

promise you that when you purchase a new MAC
4100 from a Mclntosh Franchised dealer it will be
capable of performance at or exceeding these limits
or you can return the unit and get your money back.
Mclntosh is the only manufacturer that makes this
statement.

AMPLIFIER SECTION

POWER OUTPUT

100 watts minimum sine wave continuous average

power output, per channel, both channels operating in-

to 4 ohms 20 Hz to 20 kHz, with no more than .05% total
harmonic distortion

75 watts minimum sine wave continuous average

power output, per channel, both channels operating in­to 8 ohms 20 Hz to 20 kHz, with no more than .05% total
harmonic distortion

OUTPUT LOAD IMPEDANCE
4 ohms, 8 ohms

RATED POWER BAND

20 Hz to 20 kHz

TOTAL HARMONIC DISTORTION

.05% maximum at any power level from 250 milliwatts
to rated power per channel, 20 Hz to 20 kHz, both chan­nels operating

INTERMODULATION DISTORTION

.05% maximum at any power level from 250 milliwatts
to rated power per channel both channels operating for
any combination of frequencies 20 Hz to 20 kHz

FREQUENCY RESPONSE
20 Hz to 20 kHz +0, -0.5 dB at rated power

HUM AND NOISE

Power Amp: 100 dB IHFA, 95 dB unweighted, below

rated output
Tape and Aux Input: 95 dB IHFA, 90 dB unweighted,

below rated output

Phono Input: 90 dB IHFA, 80 dB unweighted, below 10

mV input

DAMPING FACTOR

Greater than 30

INPUT SENSITIVITY AND IMPEDANCE

Power Amp: 2.5 V; 22,000 ohms
Tape and Aux: 250 mV; 100,000 ohms

Phono: 2 mV; 47,000 ohms; 87 pF

TAPE OUTPUT
Tuner: 1.0 V at 100% modulation (FM)

Tape: 250 mV with rated input

Phono: 250 mV with rated input

PROGRAM EQUALIZER

± 12 dB at 30, 150, 500, 1500, and 10,000 Hz

SENSITIVITY

2mV (11.2 dBF) IHF minimum

SIGNAL TO NOISE RATIO

70 dB IHF minimum

HARMONIC DISTORTION
Mono: 0,18% IHF maximum

Stereo: 0.38% IHF maximum

FREQUENCY RESPONSE

20 Hz to 15kHz +0, -1 dB

CAPTURE RATIO

1.8 dB

SELECTIVITY

75 dB IHF minimum

SPURIOUS REJECTION

90 dB IHF minimum

IMAGE REJECTION

80 dB IHF minimum

STEREO SEPARATION

45 dB minimum at 1 kHz
SCA REJECTION
60 dB minimum

SENSITIVITY

75 mV IHF (External antenna)

SIGNAL TO NOISE RATIO

45 dB minimum IHF, 55 dB at 100% modulation

HARMONIC DISTORTION

0.8% maximum at 30% modulation

FREQUENCY RESPONSE

3500 Hz @ -6 dB

ADJACENT CHANNEL SELECTIVITY

30 dB minimum IHF

IMAGE REJECTION

65 dB minimum, 540 kHz to 1600 kHz

SEMICONDUCTOR COMPLEMENT

45 Transistors
31 Integrated Circuits
62 Diodes

1 Silicon Controlled Rectifier

SIZE

In cabinet: 18-5/8 inches (473.1mm) wide, 6-1/2 inches
(165.1mm) high, 15-1/2 inches (393.7mm) deep. Without

cabinet: Front panel measures 17-9/16 inches
(446.1mm) wide by 5-1/4 inches (133.4mm) high.
Chassis measures 17-1/8 inches (435mm) wide by
4-15/16 inches high (125.4mm) by 13-1/2 inches
(342.9mm) deep. Knob and handle clearance required
1-1/16 inches (27mm) in front of the mounting surface.

FINISH

Front panel is clear anodized to produce a brushed

satin - silver finish with black anodized trim. Cabinet is

walnut grained vinyl.

WEIGHT
42 pounds (19 kg) net
56 pounds (25.4 kg) in shipping carton

The continuous improvement of its products is the policy of

Mclntosh Laboratory Incorporated, who reserves the right to improve

design without notice.

MECHANICAL INFORMATION

FM SECTION

AM SECTION

GENERAL

FRANCHISED DEALER

039273

MCINTOSH LABORATORY INC.

2 CHAMBERS ST., BINGHAMTON, N.Y. 13903-9990

607-723-3512

Printed in U.S.A.