McIntosh MC7100 - Compact Yet Powerful Stereo Amplifier

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General:
Super clean example of one of the best compact amplifiers you can buy. No digital nonsense here, just pure Class AB Power!

Built to the same standards and component quality as all other Mc amps from this era but in a compact chassis.  

We love the high quality and super capable speaker connectors on the back, which makes us wish they still made them like this. 

Includes single ended AND balanced XLR inputs.

Built like a tank and fully tested.

Just installed all new light bulbs to ensure decades reliability.

Featuring not one but two McIntosh Performance Certified stickers from the 1990's showing how much this piece was loved by the owner.

A Small Sampling of Performance Features Include:

SENTRY MONITOR CIRCUIT
• All power transistors have limits for the maximum amount of power they can handle. The MC7100 output transistors and power supply have been designed to allow very high current flow into properly matched load impedances. However, if a short circuit or very low load impedance is connected to the MC7100 outputs, destructive current levels could be reached if it was not controlled by the SENTRY MONITOR circuit.

THERMAL CONTROL
• All power transistors have limits to the maximum amount of heat they can safely tolerate. The MC7100 uses a highly efficient amplifying circuit which produces relatively little heat for the output power produced. The amplifier uses large area heat sinks to efficiently dissipate what heat it does generate. Natural convection air flow is sufficient for safe cool operation.

POWER GUARD
• A unique and patented feature of Mclntosh power amplifiers insures that each channel of the MC7100 will deliver full power, free of clipping distortion. A Mclntosh power amplifier with POWER GUARD will always deliver its maximum distortion free output. This power is always well above the rated power due to the Mclntosh philosophy of conservative design.

From hifi-review.com:
"The McIntosh MC7100 represents a happy combination of truly state-of-the-art performance and design, handsome styling, and electrical and mechanical ruggedness from a company that has enjoyed an enviable reputation for customer support and product reliability for almost fifty years. It is also something of a bargain for a McIntosh product. Priced well below most so-called "high-end" amplifiers, it appears to provide most of their good qualities at a price not far above those of many well-known mass-market designs. That's great engineering."

Brand Background:
McIntosh Laboratory is an American manufacturer of handcrafted high-end audio equipment based in Binghamton, New York. The company was founded in 1949 by Frank McIntosh. The company designs and produces audio amplifiers, stereo tuners and other consumer electronics products.

Cosmetic Condition:
7/10 = Good. One or two minor scratches. Well Maintained. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab and listening room.

Included:
Unit, manual, and power cord.

Packing:
Original Manufacturers Packing

Specs:
STEREO POWER OUTPUT
150 watts into 4 ohm loads or 100 watts into 8 ohm loads minimum sine wave continuous average power output per channel, both channels operating.
The output RMS voltage is:
28.3V across 8 ohms
24.5V across 4 ohms

MONOPHONIC (BRIDGED)
300 watts into an 8 ohm load minimum sine wave continuous average power output. The output RMS voltage is: 49 volts across 8 ohms.

OUTPUT LOAD IMPEDANCE
STEREO
8 or 4 ohms
MONOPHONIC
8 ohms

RATED POWER BAND
20Hz to 20,000Hz

TOTAL HARMONIC DISTORTION
0.005% maximum harmonic distortion at any power level from 250 milliwatts to rated power output.

IHF DYNAMIC HEADROOM
8 ohms, 1.7dB
4 ohms, 2.1dB

FREQUENCY RESPONSE
+ 0, -0.25dB from 20Hz to 20.000Hz
+ 0, -3.0dB from 10Hz to 100,000Hz

INPUT SENSITIVITY
1.4 volts (2.5 volts at gain control center detent)

A-WEIGHTED SIGNAL-TO-NOISE RATIO
95dB (115dB below rated output)

INTERMODULATION DISTORTION. SMPTE
0.005% maximum if instantaneous peak power output does not exceed twice the output power rating.

RATINGS
WIDE BAND DAMPING FACTOR
8 ohms, 200
4 ohms, 100

INPUT IMPEDANCE
20,000 ohms

POWER GUARD
Clipping is prevented and THD does not exceed 2% with up to 14dB overdrive at 1000Hz.

POWER REQUIREMENTS
120 volts, 50/60HZ, 3.0 amps UL/CSA

FINISH
Glass with special gold/teal nomenclature illumination. Chassis and chassis cover are black.

Dimensions:
Front panel: 17 1/2 inches (44.5cm) wide, by 3 5/8 inches (9.2cm) high.
Chassis: 14 3/4 inches (37.5cm) wide, by 2 3/8 inches (6cm) high, by 14 1/2 inches (36.9cm) deep, (from back of front panel), in- cluding connectors. Panel clearance required in front of the mounting surface is 1 inch (2.54cm).

Weight:
24 lbs.

Link to Manual:
Click Here

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - Speaker Cables - Better

Kimber Kable - Power Cords - Better

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.