McIntosh MC-275 MK V Tube Amplifier with New Matched Tubes

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Very clean example of the famous McIntosh MC275 design, in its MK V or MK 5 designation (next to newest).

The MK V sounds as good, if not better than the MK VI, and foregoes what many think to be silly LED lighting on the tubes and the more complicated speaker binding posts.

This unit was fully tested in-house, and fitted with NOS matched output tubes as described below, and new USA-made GE input tubes.

Condition is very good to excellent all around. The transformers don't have any of the typical scratches, and the chrome is super clean but some of the stenciled writing has come off the chassis. Otherwise as clean as you'll find.

Check out this video from our YouTube channel on a past MC-275 we offered for sale:

Tube Notes:

Output Tubes - Russian Svetlana KT88 - Tested both pairs with better than 10% Emission and Gm Match.

(3) 12AX7 - Current Production Russian Sovtek/Mullard - V1 Specially selected balanced triode tube.

(4) 12AT7 - NOS GE JAN 6201 (12AT7)

McIntosh MC-275 MK V Owner's Manual

Specifications (from this excellent MC275 generation comparison PDF from The McIntosh Compendium website):

MC275 [MK V]: (2009 ~ 2012)
Changes: RoHS. Gain controls eliminated. Early small 5-way plastic binding posts changed to gold metal in later production. Changes to the vertical and angled front panels.

Tubes: 4-KT88/6550 output, 3-12AX7A, 4-12AT7.

Additional Specifications:
20-20kHz (+0,-0.5dB)
Distortion: 0.5%
Noise & Hum: -100 dB
Output impedance: 4, 8, 16 ohms
Damping factor greater than 14

The SkyFi Testing Process for Amplifiers (Tube):

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.