McIntosh MA7900 Solid State Integrated Amplifier - Fiber Optic Lighting

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General:
The McIntosh MA7900 is a highly capable integrated amplifier and the first example of this model we have offered for sale. It was one of the predecessors to the current MA8950, which now carries an MSRP of $10,000.

Key features include digital inputs, iconic power meters, a five-band equalizer, and 200 watts per channel. It offers virtually everything you could want in a high-end integrated amplifier.

This unit also features McIntosh's beautiful fiber-optic lighting system, which not all McIntosh amplifiers have. The fiber-optic illumination provides the front panel with an exceptionally smooth and even glow.

Another point worth noting is this amplifier's use of McIntosh Autoformers, one of the company's signature technologies. Autoformers allow the amplifier to deliver its full 200 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.

The MA7900 is an excellent choice for anyone seeking high-end performance in a single chassis while avoiding the complexity and space requirements of separate preamplifier and power amplifier components.

Included with the amp will be its remote control, manual, and box. It will be packed with care.

SkyFi Cosmetic Notes:
The amplifier presents really well. There are some light marks on the top cover and some wear to the speaker output terminals. Overall, good.

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:
Single Owner

Connections:
RCA, XLR, IEC Power,

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, remote, manual and power cord.

Packing:
Original Manufacturers Packing

Specs:
Specifications
- Power Output: 200 watts per channel
- Frequency Response:
- +0, -0.5 dB from 20Hz–20kHz
- +0, -3 dB from 20Hz–100kHz
- Total Harmonic Distortion (THD): 0.005% maximum, both channels operating from 250mW to rated power, 20Hz–20kHz
- Intermodulation Distortion (IMD): 0.005% maximum with both channels operating, up to 400 watts instantaneous peak power, 20Hz–20kHz
- Output Load Impedance: 2, 4, or 8 ohms
- Dynamic Headroom: 2.0 dB
- Signal-to-Noise Ratio (A-Weighted):
- High Level: 95 dB
- Phono MM: 84 dB
- Phono MC: 82 dB
- Power Amplifier: 113 dB
- Sensitivity:
- High Level: 250mV (unbalanced), 500mV (balanced)
- Phono MM: 2.5mV
- Phono MC: 0.25mV
- Power Amp In: 1.4V
- Input Impedance:
- High Level: 20kΩ
- Phono MM: 47kΩ, 50pF
- Phono MC: 50, 100, 200, 400, or 1,000Ω; 100pF
- Power Amp In: 10kΩ
- Wideband Damping Factor: Greater than 40
- Maximum Input Signal:
- High Level: 8V (unbalanced), 16V (balanced)
- Phono MM: 80mV
- Phono MC: 8mV
- Power Amp In: 16V
- Preamplifier Output Impedance: 220Ω
- Headphone Impedance: 20–600Ω
- Digital Input Sample Rates:
- Optical: 16-bit/24-bit, 32kHz–96kHz
- Coaxial: 16-bit/24-bit, 32kHz–96kHz
- USB: 16-bit/32-bit, 32kHz–192kHz
- Power Control / Trigger Output: 12V DC, 25mA
- Power Requirements: 120V AC, 50/60Hz, 4.4A

Dimensions:
Width: 17.5 inches (44.5 cm), Height: 7.625 inches (19.4 cm), including feet, Depth: 22 inches (55.9 cm)

Weight:
75 lbs.

Approximate Age:
2013

Link to Manual:
Click Here

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 Summit Series BiFocal XL Bi-Wire Speaker Cables (PAIR) - Best If Applicable

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.