McIntosh MC402 Solid State Amplifier 400W - Fiber Optic

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General:
The MC-402 is the predecessor to the MC-462, and just about as capable. Featuring 400W per channel it’s capable of driving just about any load. A new MC-462 will set you back $11,500 so this is a great chance to pick of an amp just as nice for a significant discount.

We especially like it paired to B&W 800 series speakers, and just about every other large full range speaker. The sheer power of this amp means that it will pair with low sensitivity speakers well.

Key McIntosh features include use of McIntosh Autoformers, one of the company's signature technologies. Autoformers allow the amplifier to deliver its full 400 watts of output into 2-, 4-, or 8-ohm speaker loads. This feature is reserved for McIntosh's higher-end amplifiers.

It also incorporates Power Guard and Sentry Monitor protection circuits. Power Guard helps prevent audible clipping by automatically reducing input drive when necessary, while Sentry Monitor provides fuse-free short-circuit protection that automatically resets once normal operating conditions return.

Another really cool feature of McIntosh units from this era is their coveted fiber-optic lighting. Compared to the other lighting methods used in McIntosh equipment, the fiber-optic system offers the most even illumination, creating a consistent, uniform glow across the entire front panel (especially the VU meters) that many enthusiasts consider the most attractive.

It will ship for free in the continental US with fright to ensure safe transport. We have ordered a new and super strong double box with plywood reinforcement from McIntosh (which is pretty expensive), but is the only way to ensure this heavy weight amp will arrive safely. 

SkyFi Cosmetic Notes:
There is a very light mark on one of the metal trim pieces on the 3D section of the faceplate. This amp is also from a production era where the white silk screened lettering is easily damaged. Some of the lettering near the IEC power inlet is missing.

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.

Ownership:
Second Owner

Connections:
XLR, RCA, IEC Power, 5 way binding posts

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. See our detailed rating description here.

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

Included:
Unit, box , Power Cord

Packing:
Original Manufacturers Packing

Specs:
- Power Output: 400 watts per channel into stereo (2, 4, or 8 ohms) or 800 watts in mono.
- Frequency Response: 20Hz to 20kHz (+0, -0.25dB).
- Total Harmonic Distortion (THD): 0.005% max at any power level from 250 milliwatts to rated power.
- Signal-to-Noise Ratio (A-Weighted): 94dB (unbalanced), 98dB (balanced).
- Input Impedance: 10,000 ohms (unbalanced), 20,000 ohms (balanced).
- Input Sensitivity: 2.0V (unbalanced), 4.0V (balanced).
- Damping Factor: Greater than 40 (wide band).
- Dynamic Headroom: 2.1dB

Dimensions:
9-7/16 inches (23.97 cm) x 17-1/2 inches (44.45 cm) x 20 inches (50.8 cm)

Weight:
110 lbs.

Approximate Age:
2002

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Speaker Cables - Better

Kimber Summit Series Monocle XL Speaker Cables (PAIR) - Best

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

Testing Process:
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 1 KHz 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 1 KHz square wave check and a 20 Hz to 20 KHz 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 minimum. 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.