McIntosh MAC 4100 Owners Manual

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VARIOUS REGULATORY AGENCIES REQUIRE THAT WE BRING THE FOLLOWING INFOR- MATION TO YOUR ATTENTION. PLEASE READ IT CAREFULLY. WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE. The Mclntosh you have purchased is a Model MAC 4100. It has a serial number located on the rear panel of the chassis. Record that serial number here: Serial Number The model, serial number and purchase date are im- portant to you for any future service. Record the pur- chase date here: Purchase Date Upon application, Mclntosh Laboratory provides a Three-Year Service Contract. Your Mclntosh authorized Service Agency can expedite repairs when you provide the Service Contract with the in- strument for repair. To assist, record your Service Contract number here: Service Contract Number

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Your MAC 4100 Solid State AM- FM/FM Stereo Receiver will give you many years of pleasant and satisfactory performance. If you have any questions, please contact: CUSTOMER SERVICE Mclntosh Laboratory Inc. 2 Chambers Street Binghamton, New York 13903 Phone: 607-723-3512 Contents Take Advantage of 3 years of Contract Service ... Fill in the Application NOW. INTRODUCTION ...2 INSTALLATION.. .3 HOW TO CONNECT...5 WHAT THE FRONT PANEL CONTROLS DO AND HOW TO USE THEM.. .10 PUSHBUTTONS ...10 FRONT PANEL INDICATORS . . .12 BALANCING YOUR STEREO . .. 13 LISTENING TO YOUR STEREO . ..13 MAC 4100 PERFORMANCE LIMITS .. .15 TECHNICAL DESCRIPTION . .. 16 PERFORMANCE CHARTS...20,21,22,23 BLOCK DIAGRAM...24 MCINTOSH THREE YEAR SERVICE CONTRACT An application for a THREE YEAR SERVICE CONTRACT is included with this manual. The terms of the contract are: 1. Mclntosh will provide all parts, materials and labor needed to return the measured performance of the instru- ment to the original performance limits. The CONTRACT does not cover any shipping costs to and from the authoriz- ed service agency or the factory. 2. Any Mclntosh authorized service agen- cy will repair Mclntosh instruments at normal service rates. To receive service under the terms of the SERVICE CON- TRACT, the SERVICE CONTRACT CER- TIFICATE must be presented when the instrument is taken to the service agency. 3. Always have service done by a Mclntosh authorized service agency. If the instrument is modified or damaged, as a result of unauthorized repair the SERVICE CONTRACT will be cancelled. Damage by improper use or mishandl- ing is not covered by the SERVICE CON- TRACT. 4. The SERVICE CONTRACT is issued to you as the original purchaser. To pro- tect you from misrepresentation this contract cannot be transferred to a se- cond owner. 5. For your protection Mclntosh selects only dealers who have technical com- petence to guide purchasers fairly, and provide service when necessary. To receive the SERVICE CONTRACT your purchase must be made from a Mclntosh franchised dealer. 6. Your completely filled in application for a SERVICE CONTRACT must be post- marked within 30 days of the date of purchase of the instrument. 7. To receive the SERVICE CONTRACT all information on the application must be filled in. The SERVICE CONTRACT will be issued when the completely filled in application is received at Mclntosh Laboratory Incorporated in Bingham- ton, New York. Copyright 1978 © by Mclntosh Laboratory Inc. 1

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amounts of DC which turn the FET analog switches off or on. The design eliminates degradation of fre- quency response and noise pickup from long signal paths necessary with conventional switching. PHONO AMPLIFIER The phono amplifier uses a high technology in- tegrated 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 us- ed around the phono amplifier to further reduce noise and distortion. The feedback network also pro- vides precision RIAA frequency compensation. The network 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 re- quired. Input sensitivity of the phono amplifier is 2 millivolts. The gain of the amplifier is 42 dB at 1000 Hz. The phono amplifier has a very wide dynamic range. At 1000 Hz the phono input circuit will accept 100 millivolts without overload, a voltage far greater than the output of any current magnetic phono car- tridge. Phono input overload therefore is virtually im- possible. A signal level of 10 millivolts at the phono input at 1000 Hz will produce 1.2 volts at the tape output. The tape output has a source impedance of 200 ohms, designed to operate into a load im- pedance of 47,000 ohms or greater. HIGH LEVEL AMPLIFIER At the input to the high level or loudness amplifier the signal passes through the MONO/stereo switch, then through the volume control, and into the amplifier. In the past loudness controls have typical- ly used simple passive circuits connected to a tap on the volume control. As a consequence, compen- sation accuracy was dependent on many variables such as volume control position and differences in input level. The MAC 4100 uses active circuitry. The same type of integrated circuit operational amplifier that is used in the phono amplifier is used here. It has two feedback loops. One feedback loop is flat. The other feedback loop conforms to the Fletcher- Munson equal loudness compensation. A poten- tiometer is placed between these two feedback loops making it possible to select any combination of the two from a flat response to full loudness com- pensation. The overall gain of the stage is 20 dB and is not affected by the position of the loudness con- trol. EQUALIZER AMPLIFIER The equalizer amplifier uses high technology in- tegrated circuit operational amplifiers. It's output stage has been optimized for the best transient per- formance and minimum distortion. Five other opera- tional amplifiers are each arranged in a circuit con- figuration that are the equivalent of series tuned cir- cuits, one at each of the five center frequencies. Each series tuned circuit is inserted via the control potentiometer in either the input circuit or feedback circuit of the operational amplifier thereby providing a boost and cut capability of 12 dB for each band of frequencies. POWER AMPLIFIER The input impedance of the power amplifier is 22,000 ohms. It requires 2.5 volts RMS to drive the amplifier to rated output. At the input of the power amplifier two transistors are connected as a dif- ferential amplifier. The two input signals to the dif- ferential pair are the input signal and the negative feedback signal from the power amplifier. The dif- ferential amplifier permits the best use of negative feedback to maintain low noise and low distortion performance. The outputs of the differential amplifier are combined in a current mirror to a single output. This combined signal feeds a linear voltage amplifier which in turn drives two medium power driver transistors. The driver transistors feed the out- put stages. The output section is arranged as a fully complementary direct coupled series push/pull amplifier. The power transistors used in the output circuit are selected for their high power dissipation capability, wide frequency response, and large safe operating area. The power transistors are mounted on large black anodized heat sinks to assure that under normal operating conditions the transistors will operate at a low temperature. If operating temperatures should increase due to a shorted speaker or restricted ventilation, an automatic sens- ing device turns the speaker circuit off. The speaker circuit will turn on again when the temperature has returned to its normal limits. This additional protec- tion assures you of reliability even under the most extreme operating conditions. To further insure reliability a special power output SENTRY MONITORING CIRCUIT prevents failure of the power amplifier transistors due to excessive mismatch or shorting of the output. When the MAC 4100 operates normally the SENTRY MONITORING CIRCUIT has no effect on signals passing through the power amplifier. If the power dissipation in the output tran- sistors should rise above normal design limits the SENTRY MONITORING CIRCUIT restricts the drive to the output stage which reduces the dissipation in the output transistors. The SENTRY MONITORING CIRCUIT acts instantaneously for any input signal or load combination. This arrangement assures circuit reliability. Only Mclntosh gives you this degree of protection. 18