User manual MCINTOSH MC2125

[. . . ] THE MclNTOSH MC 2125 SOLID STATE STEREO POWER AMPLIFIER Reading Time: 31 Minutes Price $1. 25 Your MC 2125 Stereo Power Amplifier 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 SERVICE . 12 WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE. Take Advantage of 3 years of FREE Service . . . [. . . ] Clipping is caused when the amplifier is asked to produce more power output than it can deliver with low distortion. The extra energy content of the clipped signal will damage most speakers. A new Mclntosh advancement helps to protect your speaker from this kind of damage. The MC 2125 has a built in "waveform comparator" that compares the wave shape of the input signal with the output signal. If the non-linearity between the two signals exceeds 0. 5% a front panel signal illuminates in red (LIMIT). With the POWER GUARD switch in the NORMAL position, 1. 0% distortion will cause the POWER GUARD circuit to operate. The POWER GUARD circuit limits the input dynamically so that the amplifier cannot be overdriven which eliminates amplifier output clipping. MODE SWITCH The MC 2125 can be used in these different manners: stereo (or as a twin amplifier) and mono. Because of the excellent channel separation of the MC 2125, it can fulfill all of these functions. When the outputs are properly connected the MODE switch is used to select the method of operation desired. INPUT In the stereo or twin amplifier mode of operation both input jacks accept signal. In the mono mode of operation the Left channel input jack is disconnected and only the Right (MONO) channel input jack accepts signal. INPUT LEVEL The input sensitivity of the MC 2125 is 0. 75 volts or 2. 5 V depending on the position of the INPUT LEVEL switch. With indicated voltage applied, the amplifier will deliver its rated power. All Mclntosh preamplifiers have been designed to deliver 2. 5 volts output with rated input. For the best signal to noise ratio when using Mclntosh source equipment, always have the INPUT LEVEL switch in the 2. 5 V position and the front panel LEFT and RIGHT/ MONO GAIN controls in the fully clockwise position. For source equipment other than Mclntosh set the switch in the position nearest to the stated output rating of the source equipment. It uses 50 watts when there is no signal output and 460 watts with both channels delivering rated power. The auxiliary outlet is neither fused nor switched. 10 Performance Limits and Ratings PERFORMANCE GUARANTEE Performance Limits are the maximum deviation from perfection permitted for a Mclntosh instrument. We promise you that the MC 2125 you buy must be capable of performance at or exceeding these limits or you get your money back. PERFORMANCE Mclntosh audio power ratings are in accordance with the Federal Trade Commission Regulation of November 4, 1974 concerning power output claims for amplifiers used in home entertainment products. POWER OUTPUT STEREO watts per channel from 20 Hz to 20, 000 Hz, both channel operating MONO 0. 1% maximum harmonic distortion at any power level from 250 milliwatts to 240 watts from 20 Hz to 20, 000 Hz INTERMODULATION DISTORTION STEREO 0. 1% maximum if instantaneous peak power output is 240 watts or less per channel with both channels operating for any combination of frequencies, 20 Hz to 20, 000 Hz MONO 0. 1% maximum if instantaneous peak power output is 480 watts or less for any combination of frequencies, 20 Hz to 20, 000 Hz FREQUENCY RESPONSE (at one watt output) 20 Hz to 20, 000 Hz, +0 -0. 25 dB 10 Hz to 100, 000 Hz +0 -3. 0 dB NOISE AND HUM 95 dB below rated output 120 watts minimum sine wave continuous average power output, per channel, both channels operating into 2 ohms, 4 ohms, 8 ohms, or 16 ohms load impedance, which is; 15. 5 volts RMS across 2 ohms 21. 9 volts RMS across 4 ohms 31. 0 volts RMS across 8 ohms 43. 8 volts RMS across 16 ohms MONO RATINGS OUTPUT VOLTAGES 25 volts for distribution lines DAMPING FACTOR STEREO 16 at 2 ohms output, 50 at 4 ohms output, 20 at 8 ohms output, 14 at 16 ohms output MONO 16 at 1 ohm, 50 at 2 ohms, 20 at 4 ohms, and 14 at 8 ohms output INPUT IMPEDANCE 100, 000 ohms INPUT SENSITIVITY Switchable: 0. 75 volt or 2. 5 volts--Level control provided for higher input voltages GENERAL INFORMATION POWER REQUIREMENTS 120 volts 50/60 Hz, 50 watts at zero signal output, 460 watts at rated output SEMICONDUCTOR COMPLEMENT 45 silicon transistors 45 silicon rectifiers and diodes 8 integrated circuits MECHANICAL INFORMATION SIZE Front panel measures 16 inches wide (40. 64 cm) by 5 7/16 inches high (13. 81 cm). Chassis measures 15 inches wide (38. 1 cm) by 5 inches high (12. 7 cm) by 13 inches deep (33. 02 cm), including connectors. [. . . ] The input to the power amplifier can be attenuated to as little as one tenth, if necessary, in order to maintain low distortion in the event of excessive input signal. The POWER GUARD circuit is activated when the rear panel switch is in the NORMAL position. The LIMIT indicator operates regardless of the position of the POWER GUARD switch. METER CIRCUIT The meter circuit has three basic sections: the logarithmic amplifier, full wave rectifier, and DC amplifier. [. . . ]