McIntosh MC-2105 Vintage Audiophile Stereo Power Amplifier MC2105 Amp SERVICED For Sale

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               McIntosh MC-2105 Vintage Audiophile Stereo Power Amplifier MC2105 Amp SERVICED!! A True Classic! Serviced! In Original Box! !!!  

In the mid 1940’s Frank McIntosh headed a small firm specializing in the design and development of radio and broadcast stations. Being on the forefront of this burgeoning industry he saw the many shortcomings of the professional equipment of the day. Most notably was the need for high-powered, low distortion amplifier.  Hiring engineer Gordon Gow as his assistant the duo researched and developed a landmark amplifier. The amplifier was so far superior in output and distortion specs it was at first met with disbelief. The audio test equipment of the day was not designed to test an amp of such exceeding performance characteristics. But the proof was in its performance. Word of mouth spread and demand grew thus Frank McIntosh & Gordon Gow had new day jobs and McIntosh Laboratory was born. Hindsight confirms the company introduced a new era of professional audio excellence and they were amongst the first to market professional equipment to the consumer. Thus nurturing the high-fidelity industry and spearheading it for years to come.

For more than six decades McIntosh has maintained dominance in the high-end audio industry. They are the only surviving “foundational” high fidelity equipment manufacturer around today, still headquartered in Binghamton, New York, with operation and manufacturing carried out in the same method of the originators.  McIntosh’s permanence in the marketplace is owed to its history of phenomenal components, all adhering to the same design criterion set forth by Frank McIntosh and Gordon Gow; superior sonic performance and unmatched reliability. Every component was created with capacity so great that it will never be operated at or near its stress point.  A good reason why an estimated 80% of the McIntosh components produced since 1949 are still in use today and what’s more amazing is these same components are outperforming modern counterparts with the benefit of years of technological progression.  When you buy a McIntosh you’re buying a lifetime component!

When introduced in 1967 the McIntosh MC-2105 was a revolutionary amp in many respects and served as the blueprint for all future McIntosh amps to come. Not only was it McIntosh’s first 100 watt x2 solid state amp ever, it was also their first to have a full glass panel faceplate, precision calibrated output level meters, the panloc mounting system, and  it was the 1st sold state amp to incorporate McIntosh’s famed Unity Coupled Autoformer for full rated output at 4,8, or 16 Ohm impedances. Its meter layout and chassis design also influenced the look of the emerging solid state amplifier in general, as other equipment manufacturers were quick to try and follow the leader. But most importantly the most defining aspect of the MC2105 is that it was one of the very first solid state amplifiers to actually sound good, and it easily set a new standard of performance excellence in its era.

Today the MC2105 is still loved for the same reasons it was 45 years ago. It has a timeless sonic signature that make listening to music so easy to do.  From top to bottom the amp has a free flowing smoothness that is in contrast to the harshness of so many solid state amps of its era. Its sound is liquid with a lot of punch and solidity at the bass end and very defined mid and high frequencies. Some of the many features and functions of the MC2105 include;

Three Separate Power Supply Sections One positive and one negative high current supply is used for the output stages. The other positive supply is used for the driving amplifier stages. All supplies are full wave and use silicon rectifiers. Adequate filtering is used to assure an absolute minimum of hum. The power output stage filter capacitors have very high capacity, which allows full power output below 20Hz. The power transformer is very generous in size and runs cool, even under heavy use.      
• Two Stage Amplifier & Two Stage Preamplifier each individual amp/preamp stage is efficiently overbuilt in order to provide tremendous power with the very least amount of distortion. The build quality is so great that it will never reach high stress levels, thus lasting indefinitely.   
• Push-Pull Output Section The output section is arranged as a series push-pull amplifier. The power transistors used in the output section are hand selected for their high power dissipation capability, wide frequency response, and large “safe operating area”   
• Oversized Anodized Heat Sinks The power transistors are mounted on the large heat sinks to insure they will continue to operate at low temperatures.   
• McIntosh Autoformer Unlike any other amplifier, the Autoformer allows the 2105 to deliver full power at all speaker impedances, you are not penalized for your choice of speakers. There is no danger of exceeding safe limits or overheating. Another advantage of the Autoformer is the 25 volt output for constant voltage distribution system. With the 2105 several sets of speakers can be operate independently throughout your home. The Autoformer also protects the speakers from damage in the event of amplifier failure. Should a direct current component appear at the amplifier output, it is shunted by the low DC resistance of the Autoformer, instead of passing through the speaker voice coil, which could damage the speaker or even cause a fire.   
• Sentry Monitoring Circuit Prevents failure of the power output transistors due to excessive mismatch of the output. When the 2105 operates normally the Sentry Monitoring Circuit has no effect on the signal passing through the power amplifier. If the power dissipation should rise above normal operation, the Sentry Monitoring Circuit restricts the drive to the output transistors. The Sentry Monitoring Circuit acts instantaneously for any input signal or load combination. This arrangement assures complete circuit reliability.   
• Temperature Sensing Circuit If amp temperature increases due to a shorted speaker, or restricted ventilation, an automatic temperature sensing device turns off the 2105. The device operates automatically at a preset temperature. The 2105 will turn on again when the temperature returns to normal.   
• Dual Power Level Meters for each channel a highly accurate peak meter is provided. Because of unique circuitry these meters are able to provided instantaneous and precise changes in musical program with an accuracy rate of over 98%.  Additionally a four position (off, -20, -10, 0) meter range switch is provided to correspond with gain level.   
• Individual Left & Right Gain for balancing output of each channel  
• And Much More!       

Power Output105 RMS watts continuous perchannel into 4,8,or 16 ohms, both channels operating.Harmonic DistortionWill not exceed 0.25% at105 watts output from 20 Hz to 20,000 Hz, both channels operating.Typical performance is less than 0.1% at rated power. Distortiondecreases as output power is reduced.Intermodulation DistortionWill not exceed0.25% is instantaneous peak power output power is 210 watts or lessper channel with both channels operating for any combination offrequencies 20 Hz to 20,000 HzFrequency Range20 Hz to 20,000 Hz +0 -0.1 dBat rated power
15 Hz to 60,000 Hz +0 -0.5 dB at rated power
10Hz to 100,000 Hz +0 -3.0 dB at one-half rated power.Noise & Hum90 dB below rated outputOutput Power Monitor MeterMeter is calibratedto  read +3 dB when amplifier produces 100 watts. Meter range switchis provided to increase meter sensitivity by 10 dB or 20 dB
Meterfeatures special circuit to respond to peak value of complex inputsignal. Calibration accuracy at 0 dB reading is +-2% at allfrequencies; meter range accuracy is +-5%Output Impedance4, 8, and 16 ohmsOutput Voltage25 voltsDamping Factor18 at 4 ohms output
13 at 8ohms output
10 at 16 ohms outputInput Impedance200,000 ohmsInput Sensitivity0.5 volt. Level controlprovided for higher input voltage.Power Requirements117 volts, 50/60 Hz, 75watts at zero signal output. 430 watts at rated outputSemiconductor Complement34 silicontransistors
18 silicon rectifiers and diodesDimensions16 3/16” W x 7 1/8” H x 15 1/4” D
Original box:  20 1/2” x 20 1/2” x 11 1/2” HFinishFront Panel: Anodized gold &Black
Chassis: Chrome & BlackMountingConvenient, professional PANLOCWeight 59.5 lbs unpacked+12.5 lbs for original box (unit will be shipping in secondary box over original box)
Special FeaturesThe amplifier is completelystable when connected to any loud speaker system or even to anyreactive loads. The MC2105 has special circuits to prevent damage byshort circuit or open circuit of the output loads, or by any amount ofoutput impedance mismatch.
Thermal cutouts are mounted on theoutput transistor heat sinks to provide protection in the event ofinadequate ventilation.

Amp was gone through by an authorized McIntosh tech. All components that did not test within specification were replaced. Which includes 6 capacitors and associated components.  All lamps were replaced where needed, all switches and controls were properly cleaned.  Unit was then tested on an Audio Precision ATS-1 Test Set and exceeds the manufacturer’s specifications.  All features and functions are working flawlessly. Unit sounds great. Cosmetically amp is clean, though has some blemishes. The faceplate has the typical bubbling around headphones and along lower edge. Chassis has some minor scratches. New gold plated RCA jacks were installed. Original owner’s id # is tastefully etched on rear of the chassis in inconspicuous location. The dividers on the speaker output terminals broken off in a few spots, does not effect function.

This is a sale so it will go to the highest buyer. Winning buyer pays $79.75 for careful shipping, packaging, & insurance in the continental U.S.
International buyers welcome and pay only actual shipping price, no handling fee.Please note: the item pictured is guaranteed to be the actual item you will receive. None of my pictures are taken off other peoples pages or web sites, so offer with confidence - what you see is what you get! PayPal and any other approved payments gladly accepted! (please email for details) Never a handling fee, buyer pays actual shipping as stated above.

International buyers welcome.

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