User manual MCINTOSH MC2255

[. . . ] THE MclNTOSH MC 2255 SOLID STATE STEREO POWER AMPLIFIER Reading Time: 31 Minutes Price $2. 00 VARIOUS REGULATORY AGENCIES REQUIRE THAT WE BRING THE FOLLOWING INFORMATION 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 MC 2255. Record that serial number here: Serial Number The model, serial number and purchase date are important to you for any future service. Record the purchase date here: Purchase date Upon application, Mclntosh Laboratory provides a Three-Year Service Contract. [. . . ] Two switches control the speed of the countdown (SLOW or FAST) and the presence of the beep tone (ON-OFF). 10 ON: Music will be heard through the loudspeakers. Use this as the normal listening position. Rear Panel information MODE SWITCH The MC 2255 will operate in three modes, Stereo, Mono Bridge, and Mono Parallel. The Mono modes differ in the loads they will drive and the connection sequence to the speaker terminals. LEFT and RIGHT OUTPUT TERMINALS 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. AC POWER For stereo operation, output impedances of 1, 2, 4 and 8 ohms have been provided on a secure, screw type barrier strip. For monophonic operation proper interconnection provides 0. 5, 1, 2, 4, 8, and 16 ohms from the same barrier strips. See page 5 for connecting instructions. INPUT JACKS The input to the MC 2255 is 120 volts 50/60 Hz at up to 12 amps. The primary circuit is protected by a 15 Amp Fuse. In the stereo mode of operation, both input jacks accept signal. In the mono mode of operation only the Right (MONO) channel input jack accepts signal and the Left channel input jack is disconnected. INPUT LEVEL The Input sensitivity of the MC 2255 is 0. 75 volts or 2. 5 V depending on the position of the INPUT LEVEL switch. 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, place the INPUT LEVEL switch in the 2. 5 V position and the front panel LEFT and 11 Performance Limits PERFORMANCE GUARANTEE Performance Limits are the maximum deviation from perfection permitted for a Mclntosh instrument. We promise you the MC 2255 you buy must be capable of performance at or exceeding these limits or you get your money back. INTERMODULATION DISTORTION STEREO 0. 02% maximum if instantaneous peak power output is 500 watts or less per channel with both channels operating for any combination of frequencies, 20 Hz to 20, 000 Hz. MONO 0. 02% maximum if instantaneous peak power output is 1000 watts or less for any combination of frequenices, 20 Hz to 20, 000 Hz. FREQUENCY RESPONSE (at one watt output) 20 Hz to 20, 000 Hz + 0 - 0. 25 dB. INPUT SENSITIVITY Switchable: 0. 75 volt or 2. 5 volts--level control provided for higher input voltages. POWER GUARD Clipping is prevented and THD does not exceed 2% with up to 20 dB overdrive at 1 KHz. 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 250 watts minimum sine wave continuous average power output, per channel, both channels operating into 1 ohm, 2 ohms, 4 ohms, or 8 ohms load impedance, which is: 15. 8 volts RMS across 1 ohm 22. 4 volts RMS across 2 ohms 31. 6 volts RMS across 4 ohms 44. 7 volts RMS across 8 ohms MONO 500 watts minimum sine wave continuous average power output in to 0. 5 ohm, 1 ohm, 2 ohms, 4 ohms, 8 ohms, or 16 ohms load impedance, which is: 15. 8 volts RMS across 0. 5 ohm 22. 4 volts RMS across 1 ohm 31. 6 volts RMS across 2 ohms 44. 7 volts RMS across 4 ohms 63. 2 volts RMS across 8 ohms 89. 4 volts RMS across 16 ohms OUTPUT LOAD IMPEDANCE STEREO 1 ohm, 2 ohms, 4 ohms, and 8 ohms; separate terminals are provided for each output. MONO-PARALLEL 0. 5 ohm, 1 ohm, 2 ohms, and 4 ohms; obtained by connecting together the appropriate terminals of both channels. MONO-BRIDGED 2 ohms, 4 ohms, 8 ohms, or 16 ohms, balanced to common connections. RATED POWER BAND 20 Hz to 20, 000 Hz TOTAL HARMONIC DISTORTION STEREO 0. 02% maximum harmonic distortion at any power level from 250 milliwatts to 250 watts per channel from 20 Hz to 20, 000 Hz, both channels operating. MONO 0. 02% maximum harmonic distortion at any power 12 GENERAL INFORMATION POWER REQUIREMENTS 120 volts 50/60 Hz 0. 7 to 12 amps. [. . . ] The logarithmic amplifier consists of a high gain operational amplifier with a biopolar connected silicon diode pair as feedback elements. These diodes have a uniform logarithmic characteristic over an 80 dB range. The full wave rectifier circuit uses an operational amplifier with silicon diode feedback networks. This amplified diode circuit has nearly perfect rectification characteristics. [. . . ]