McIntosh MC 2100 power amp

 

The Solid State Stereo Power Amplifier

A two stage preamplifier with three transistors in each channel increases the input voltage 16 dB .

There are 13 transistors in each power amplifier section. The two stage preamplifier is fed to a pair of matched transistors arranged as an emitter coupled amplifier with two inputs and one output. The signal from the preamplifier section connects to one of these inputs. Both AC and DC negative feedback are applied to the other input. This large quantity of feedback is used to reduce noise and distortion. The signal is then fed to a voltage amplifier. The voltage amplifier is followed by two driver transistors.

The output section is arranged as a series push-pull amplifier. The power transistors used in the output section of your MC 2100 are selected for their high power dissipation capability, wide frequency response, and large "safe operating area." In addition, each power transistor is given four separate tests before it is put in your MC 2100. This additional testing makes sure your MC 2100 will deliver its rated power from 20 Hz to 20 kHz with low distortion and complete reliability. 

The power transistors are mounted on oversized anodized heat sinks. The heat sinks assure that under normal operation the transistors will operate at a low temperature. If temperatures increase due to a shorted speaker, or restricted ventilation, an automatic temperature sensing device turns off the MC 2100. The device operates automatically at a preset temperature. The MC 2100 will turn on again when the temperature has returned to normal limits. This additional feature gives your MC 2100 complete reliability under the most extreme operating conditions.

The output stages are matched to the load by the Mclntosh autoformer. The Mclntosh autoformer is carefully wound using Mclntosh trifilar winding and interleaving techniques. Trifilar winding and interleaving gives the autoformers exceptional bandwidth. The autoformers properly match the power transistors to 4, 8, and 16 ohms loads at all audio frequencies.

The use of the Mclntosh designed trifilar autoformer makes the Mclntosh solid state amplifiers the only amplifiers that deliver Full Power at All Speaker Impedances. You have not been power penalized for your choice of loudspeakers when using the Mclntosh MC 2100.

 Another of the advantages of the autoformers is the 25 volt output for a constant voltage distribution system. With the MC 2100 several sets of speakers can be operated independently throughout your home.

To further insure reliability a special power output Sentry Monitoring Circuit prevents failure of the power output transistors due to excessive mismatch of the output. When your MC 2100 operates normally the Sentry Monitoring Circuit has no effect on signals 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. Only Mclntosh gives you this degree of protection.

There are 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 20 Hz. The power transformer is generous in size and runs cool, even under heavy use.

 

Specifications

Power Output

Stereo :  105 watts (continuous, per channel, both channels operating, which is):

20.5 volts RMS across 4 Ω 

29.0 volts RMS across 8 Ω 

41.0 volts RMS across 16 Ω 

Mono :  210 watts (continuous, which is):

20.5 volts RMS across 2 Ω 

29.0 volts RMS across 4 Ω 

41.0 volts RMS across 8 Ω 

Harmonic Distortion

Stereo :  Will not exceed 0.25% at any power level to 105 watts output per channel from 20 Hz to 20,000 Hz both channels operating. Typical performance is less than 0.1% at rated power. Distortion decreases as output power is reduced

Mono :  Will not exceed 0.25% at any power level to 210 watts output from 20 Hz to 20,000 Hz. Typical performance is less than 0.1% at rated power. Distortion decreases as output power is reduced

Intermodulation Distortion

Stereo :  Will not exceed 0.25% if instantaneous peak power is 210 watts or less per channel with both channels operating for any combination of frequencies 20 Hz to 20,000 Hz

Mono :  Will not exceed 0.25% if instantaneous peak power is 420 watts or less for any combination of frequencies 20 Hz to 20,000 Hz

Frequency Response:

20 Hz to 20,000 Hz (+0 -0,25 dB) at rated power

15 Hz to 60,000 Hz (+0 -0,5 dB) at rated power

10 Hz to 100,000 Hz (+0 -3,0 dB) at one-half rated power

Noise and Hum:  90 dB or more below rated output

Output Impedance

Stereo :   4, 8, and 16 Ω 

Mono :  2, 4, and 8 Ω 

Output Voltages: 25 volts (stereo and mono)

Damping Factor:

20 at 4 Ω  output

14 at 8 Ω  output

11 at 16 Ω  output

Input Sensitivity:  0.5 volt. (Level control provided for higher input voltage)

Input Impedance: 200,000 Ω 

Power Requirements: 

120 volts 50/60 Hz, (50 watts at zero signal output)

450 watts at rated output

Semiconductors:  32 silicon transistors;  14 silicon rectifiers and diodes

Dimensions (W x H x D): 298,5 x 196,9 x 431,8 mm  (11" x 7" x 17")

Chassis:  Chrome and black.

Weight:  25,86 kg (57 pounds) 

 

Special Features: 

The amplifier is completely stable when connected to any loudspeaker system or even to any reactive loads. The MC 2100 has special circuits to prevent damage by short circuit or open circuit of the output loads, or by any amount of output impedance mismatch. Thermal cutouts are mounted on the output transistor heat sinks to provide protection in the event of inadequate ventilation.

Performance Limits are the maximum deviation from perfection permitted for a Mclntosh instrument. We promise you that the MC 2100 you buy must be capable of performance at or exceeding these limits or you get your money back. Mclntosh is the only manufacturer that makes this guarantee.