McIntosh MC2105 Solid State Vintage Amplifier - RESTORED, UPGRADED, PERFECT

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We recently restored three of these classic beauties and boy were the results worth the trouble! Perfect is also not a word we throw around lightly here, but in this case it's warranted.

Classic McIntosh looks - but with a vintage feel. Absolutely gorgeous, and capable of powering most modern and vintage speakers.

Priced accordingly, so if you're looking for an unserviced bargain on a 50 years "young" piece of audio excellence, please look elsewhere.

Restoration Notes:

This MC2105 underwent an extensive restoration which involved a full recap of the unit with the exception of the large filter capacitors and multi-section power supply cap which both tested very well.

We also replaced all of the signal transistors in the unit with modern devices to ensure stable bias and long term reliability.

Special care was taken in parts selection for signal path caps. Nichicon Muse Bi-Polar electrolytics and WIMA stacked film caps were used in sensitive sections of the input board. All other electrolytic capacitors were replaced with modern long life axial equivalents to maintain the original look of the amplifier.

All controls have been cleaned and verified. The meters have also been calibrated to service manual specifications.

This amp passed all of our post restoration stress tests and hits the 105W RMS power rating with ease. The chrome chassis and back panel have been detailed.

We also re-lamped the unit with LEDs, resulting in a stunning presentation of the classic McIntosh front panel.

Cosmetic Notes:

- Light scratching on the lamp panel and transformers

- Mild chrome wear on back panel and edges

McIntosh MC2105 Manual

Performance Limits and Ratings

PERFORMANCE
McIntosh 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
105 watts minimum sine wave continuous average power output, per channel, both channels operating into 4 ohms, 8 ohms, or 1.6 ohms load impedance, which is:
20.5 volts RMS across 4 ohms
29.0 volts RMS across 8 ohms
41.0 volts RMS across 16 ohms

OUTPUT LOAD IMPEDANCE
4 ohms, 8 ohms, or 16 ohms; separate terminals are provided for each output

RATED POWER BAND
20 Hz to 20,000 Hz

TOTAL HARMONIC DISTORTION
0.25% maximum harmonic distortion at any power level from 250 milliwatts to 105 watts per channel from 20 Hz to 20,000 Hz, both channels operating

INTERMODULATION DISTORTION
0.25% if instantaneous peak power output is 210 watts or less per channel with both channels operating for any combination of frequencies 20 Hz to 20,000 Hz

FREQUENCY RESPONSE
20 Hz to 20,000 Hz +0 -0.25 dB
10 Hz to 100,000 Hz +0 -3.0 dB at one watt output

NOISE AND HUM
90 dB below rated output

OUTPUT POWER MONITOR METER
Meter is calibrated to read +3 dB when amplifier produces 105 watts. Meter range switch is provided to increase meter sensitivity by 10 dB or 20 dB Calibration accuracy at 0 dB reading is ±2% at all frequencies; meter range accuracy is ±5%

RATINGS
OUTPUT VOLTAGES
25 volts for distribution lines

DAMPING FACTOR
13 at 8 ohms output 18 at 4 ohms output 10 at 16 ohms output

INPUT IMPEDANCE
200.00 ohms

INPUT SENSITIVITY
0.5 volt. Level control provided for higher input voltage

GENERAL INFORMATION
POWER REQUIREMENTS
120 volts 50 60 Hz, 75 watts at zero signal output, 430 watts at rated output

SEMICONDUCTOR COMPLEMENT
34 silicon transistors
18 silicon rectifiers and diodes

MECHANICAL INFORMATION
SIZE
Front panel measures 16 3/16 inches wide (41,12 cm) by 71/8inches high (18,1 cm). Chassis measures 15 inches wide (38,1 cm) by 6 9/16 inches high (16.67 cm) by 141⁄2 inches deep (36.83 cm), including connectors. Knob clearance required is 11⁄2 inches (3.81 cm) in front of mounting panel

FINISH
Front panel is anodized gold and black with special gold teal nomenclature illumination. Chassis is chrome and black

MOUNTING
Exclusive Mclntosh developed professional PANLOC

WEIGHT
65 pounds (29.48 kg) net, 77 pounds (34,93 kg) in shipping carton

SPECIAL FEATURES
The amplifier is completely stable when connected to any loudspeaker system or even to any reactive loads; The MC 2105 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.

Peak reading - peak locking meters feature special circuit to respond to peak value of complex input signal

The SkyFi Testing Process for Solid State Amplifiers:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and tubes are inspected for signs of stress overheating or cracking.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If it all looks clean we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier the remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will also be tested.

We also test all tubes for output gain and leakage on our calibrated B&K 747 tester against the original manufacturers specifications. If needed, the tubes will be replaced from our vast NOS (New Old Stock) vintage or modern inventory.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage KEF speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.