McIntosh MC2250 Amplifier - Under 500 In Existence - Serviced and Super Clean

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This is a rather rare MC2250 which had low production numbers of 499 total produced back in the mid-1980's.

It's the very first one we've ever seen at the shop and were quite impressed.

It features that typical McIntosh warm sweet sound along with vintage cosmetics rather than glass/meters.

A perfect match for a C22 or other preamp with a champagne faceplate. Simply let us know if you want help picking one for your system.

Extremely clean and working perfectly.

Service notes from our technician:
• Previously Serviced by the experts over at Audio Classics
• Tested up to full manufacturer rated power no problems whatsoever
• Channels reviewed and balanced
• McIntosh Power Guard working just like it should
• Audio Classics did some work on the DC Offset pots and did a routine service on the unit (please see our last photos for full details).

The shipping carton is also a very nice Audio Classics custom box. Probably safer than original factory packaging.

McIntosh MC2250 Amplifier - Owner's Manual

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - Speaker Cables

Technical Specifications:

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 into 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 level from 250 milliwatts to 500 watts from 20 Hz to 20,000 Hz.

INTERMODULATION DISTORTION
STEREO
0.02% maximum if instantaneous peak power out- put 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 out- put is 1000 watts or less for any combination of frequences, 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 + 0.25 - 1 dB.

NOISE AND HUM
95 dB below rated output.

DAMPING FACTOR
Greater than 30

INPUT IMPEDANCE
50,000 ohms.

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.

POWER REQUIREMENTS
120 volts 50/60 Hz 0.7 to 12 amps.

SEMICONDUCTOR COMPLEMENT
76 silicon transistors
37 silicon rectifiers and diodes
9 integrated circuits

SIZE
Front panel measures 16 inches wide (40.7 cm) by 6-31/32 inches high (17.7 cm). Chassis measures 14-9/16 inches wide (37 cm) by 6-1/2 inches high (16.5 cm) by 14-1/2 inches deep (36.8 cm), including connectors. Knob clearance required is 1 inch (2.5 cm) in front of mounting panel

FINISH
Front panel is anodized gold. Chassis is chrome and black

WEIGHT
80 pounds (36.3 kg) net
94 pounds (42.6 kg) in shipping carton

The SkyFi Testing Process for Solid State Amplifiers:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a controlled power on sequence using a Sencore safety analyzer to monitor current draw in real time. Once the amplifier is determined to be safe to operate, we connect it to full AC mains for function and power testing. We connect the speaker outputs of the amplifier to a Sencore PA81 Power Analyzer which acts as a dummy load, DC offset monitor, and oscilloscope interface. We start with a low level 1KHz test signal at the amplifier’s input and slowly increase its amplitude while monitoring the output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping. At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. If the device under test has both balanced and single ended inputs they are both tested at this time. We finish off the bench evaluation with a 1KHz square wave check and a 20Hz to 20KHz sine sweep to assess the amplifier’s frequency response characteristics. This battery of tests will usually reveal if the amplifier has any issues that need further attention.

Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.

If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when the unit has fully come up to temperature.