McIntosh MAC 4280 receiver

  

The MAC 4280, a high quality FM/AM receiver, has many useful features to enhance your listening and video enjoyment. The Mcintosh Remote Control provides unusual varsatility with operating simplicity. It provides remote control in the main listening area and can be expanded to provide control from an additional area. In each area:  You can turn the AC power On or off;  You can select the listening sound source;  You can adjust the volume;  When the tuner section is the sound source, you can select the stations you wish to hear on either FM or AM, or select from the preset stations on either FM or AM;  When a Mcintosh CD player is the sound source, you can put the cD player in the play mode, shift to the next track or the preceeding track on the disc or stop play from the disc;  You can mute the sound.

Your listening commands are executed by pressing buttons on the hand-held remote controller. When you press a button the controller transmits, via an infrared beam, a command signal. The receiver for these signals is an infrared sensor in the MAC 4280 or a Mcintosh R607 remote Sensor.

A rear panel connector provides the input for rmote control from a second area. With the addition of a Mcintosh R607 Remote Sensor, all of the command capabilities of the main area can be executed in the second area.

Some of the features of the MAC 4280 are:

This "state-of-the-art." FM/AM tuner displays the station frequencies digitally. Stations are selected easily by the preset pushbuttons tuned with the manual tuning knob, or you can scan upp or down either broadcast band. When the stations assigned frequency is displayed, tuning is locked and held to the precise center of the broadcast channel. When the pushbutton presets have been programmed, the electronic memory will store and retain your 5 favorite stations on FM and Am, for instantaneous recall.

The tuning memory is retained for a week even though the receiver should become disconnected from the AC power line.

 

Separate listen,, and record facilities, introduced and perfected by Mcintosh, permit tape recording one program while listening to a second program. Separate input selectors, electrically isolated from each other, provide non interference operation in both listen and record. You can record on 2 tape recorders from any source and you can easily copy from one tape recorder to another.

Three separate tone shaping controls provide tone shaping. Each control adjust selected frequency bands to satisfy your personal preference or the demands of the program material.. At the detent in the center of the rotation of each control the equalizer circuits are disconnected, completely removed from the operating circuits.

Technological leadership is shown in the full power mcintosh amplifier which will deliver its maximum power output to one or two pairs of loudspeakers. The quality of the sound reproduction and the quality of your speakers are protected by the patented Mcintosh Power Guard circuit. The Power Guard waveform comparison circuit detects waveform differences between the input and the output signal. A sampling of the program material at the output of the amplifier is constantly compared with the program material at the amplifier input. Should the differences reach 0,5% , Power Guard goes to work. In only a fraction of a millisecond Power Guard dynamically reduces input level to prevent amplifier overload yet permits the amplifier to deliver its absolute maximum power output without extra distortion. The operation of the Power Guard circuit is absolutely silent. There is not even "soft" clipping. There is simply no clipping.

The patented Sentry Monitoring circuit constantly monitors the output signal. At signal levels up to rated output this circuit has no effect. If the power output exceeds design maximum, or in the event of a short circuit ir severe mismatch, the Sentry Monitoring circuit protects the output transitors from failure.

All in all, your selection of the Mcintosh MAC 4280 FM/AM Receiver will be reinforced by your day-to-day use of this superb instrument.

 

Specifications

Amp Section

Stereo Power Output (minimum sine wave continuous average power output per channel, from 20 to 20,000 Hz, with both channel operating): 

100 watts across 4 Ω loads,

75 watt accros 8 Ω loads

Power Bandwidth:  20 Hz to 20,000 Hz

Total Harmonic Distortion:  0,03% maximum at any power level from 250 mV to raated power per channel, 20 to 20,000 Hz, both channels operating

Intermodulation Distortion:  0,03% maximum if instantaneous peak power output is 200 watts or less across 4 Ω, or 150 watts or less across 8 Ω with both channels operating for any combination of frequencies, 20 Hz to 20 kHz

Frequency Response:  20 Hz - 20,000 Hz +0 -0,5 dB at rated power

Input Sensitivity

Phono MC :  0,12 mV produces rated output

Phono MM :  2,5 mV produces rated output

Tape, Aux ;  250 mV produces rated output

Power Amp :  1,5 V produces rated output

Signal-to-Noise Ratio (A-weighted)

Power Amp :  100 dB below rated output

Tape, Aux :  95 dB below rated output

Phono :  90 dB with 10 mV input

Maximum Input Signal

Phono MC :  4,1 mV

Phono MM :  80 mV

High Level :  8 V

Input Impedance

Phono MC :  100 Ω

Phono MM :  47 k Ω

Tape, Aux ;  20 k Ω

Power Amp :  18 k Ω

Damping Factor:  greater than 50 at 8 Ω

Tape Output

Phono :  250 mV with rated input

Tape :  250 mV with rated input

Tuner :  1,0 V at 100% modulation

Program Equalizer:  ±12 dB at 30, 750 and 10,000 Hz

FM Section

Uasble Sensitivity:  11,25 dBf which is 1,0 µV across 75 Ω

50 dB Quieting Sensitivity:

Mono :  15,2 dBf which is 1,6 µV across 75 Ω

Stereo :  27 dBf which is 6 µV across 75 Ω

Signal-to-Noise Ratio

Mono :  80 dB

Stereo :  75 dB

Frequency Response:

Mono :  ±0,5 dB from 20 to 15,000 Hz

Stereo :  ±0,5 dB from 20 t0 15,000 Hz

Total Harmonic Distortion Mono:

0,15% at 100 Hz

0,1% at 1 kHz

0,1% at 10 kHz

Total Harmonic Distortion Stereo

0,1% at 100 Hz

0,1% at 1 kHz

0,25% at 10 kHz

Intermodulation Distortion

Mono :  0,1%

Stereo :  0,2%

Capture Ratio:  1,5 dB

Alternate Channel Selectivity:  60 dB

Spurious Response:  95 dB

Image Response:  90 sb

AM Suppression:  60 dB

Stereo Separation:

35 dB at 100 Hz

45 dB at 1 kHz

40 dB at 10 kHz

SCA Rejection:  65 dB

AM Section

Sensitivity:  25 µV (external antenna)

Signal-to-Noise Ratio

50 dB at 30% modulation

60 dB at 100% modulation

Harmonic Distortion:  1,0% maximum at 50% modulation (0,2% typical)

Frequency Response:  30 Hz to 3,5 kHz +0 -6 dB

Adjacent Channel Selectivity:  50 dB minimum IHF

Image Rejection:  50 dB minimum

IF Rejection:  55 dB minimum

General Information

Semiconductors:  118 Silicon Diodes;  13 Varactor Diodes;  32 LED;  2  I.R. Emitting Diodes;  1 I.R. Photo Diode:  4 Seven Segment LED Displays;  3 Opto Couplers:  68 Bipolar Transitors:  3 Field Effect Transistors;  59 Integrated Circits

Remote Controller:  HR 4280 - 22 button infrared hand held controller

Power Requirements:  120 V, 50/60 Hz

Power Consumption:  60 to 575 watts

Dimensions (W x H x D):  464 x 133 x 394 mm   (18-1/4" x 5-1/4" x 15-1/2")

Weight:  13,1 kg (29 pounds)

Finish: 

Front panel is brushed black anodized aluminium with gold anodize trim

Side panels are machined solid walnut with satin lacquer finish