McIntosh MA2275 All Tube Integrated Amplifier, Super RARE!

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General:
I've been back and forth over the past few months if we should offer up this MA2275 for sale, or keep it in our private collection. 

You see, the MA2275 is a sort of rare bird in the world of McIntosh for the following reasons. 

1) Low production numbers and scarcity. At the time of writing this listing there are zero other units I could find. The last known sale we found in the US goes back almost five years to 2017. Most of the MA2275's were sold in the Asian market where large integrated tube units were marketable. 

2) This is the only ALL TUBE integrated McIntosh ever produced in its long history. Sure there are plenty of integrated models, but they are mostly solid state or hybrid solid state and tube designs.

3) The MA2275 uses tubes for ALL stages, not just the output. Most integrated tube amps resort to transitors for the preamp stage to keep costs down. Even the phono stage is tubed! 

4) This is a complete collector set including the original McIntosh carton, packing, manual, AND remote.  As added bonus a fresh current production McIntosh remote will be provided with this unit along with the original remote control.

5) Great reviews, check this one our for example: http://www.hifi-review.com/153660-mcintosh-ma2275.html

6) The MA2275 is based on the legendary MC275 amplifier with the addition of 2 ohm speaker taps, making it capable of driving even the most difficult loads. 

If you're a collector or someone that must have a fully tubed integrated, the MA2275 might be right for you. 

Sure this piece commands a big number due to its rarity. It would be comparable in performance and features to a current MC275 and a C22 preamp which would cost about the same. Another great alternative at this price range would be the MA12000 which would give you quite a bit more power, a DAC and EQ.

Cosmetic condition is very good with little signs of use. Functionally it just received a light service and is working properly. We replaced the tubes with a strong matching set.

It will also ship via freight anywhere within the lower 48 US States, strapped to a pallet due to its weight and for safe travels. Yes you'll need 1-2 friends to help you unbox safely.

Notes:
• Power testes both channels up to 75W - Clean
• Phono test passed
• Balanced test passed
• All inputs and controls tested
• Remote works
• Listening Test Pass 

McIntosh Performance Features Include:
• Power Output
The MA2275 has two separate power amplifier channels, each capable of 75 watts into 2, 4 or 8 ohm Loudspeakers.
• Bifilar Wound Transformers and Output Circuit 
The Power Output Circuitry utilizes the famous McIntosh Patented Unity Coupled Circuit with a Bifilar Wound Output Transformer for low distortion, extended frequency response and cool operating output tubes.
• Balanced and Unbalanced Inputs
The MA2275 has five Inputs for high level program sources and one Phono Input for a Moving Magnet Cartridge.
• Tone Control Bypass
The Bass and Treble Control Circuit Elements can be removed from the Signal Path.
• Gold Plated Connectors and Tube Socket Contacts 
Gold Plated Input Jacks and Output Binding Posts provide trouble free connections. Ceramic tube sockets with gold plated contacts provide protection from atmospheric contamination. Output Tube Sockets include Air-Pipe cooling at their bases.
• Super Mirror Chassis Finish
The Stainless Steel Chassis with Super Mirror Finish ensures the pristine beauty of the MA2275 will be retained for many years.

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 inputs and outputs, XLR inputs for CD, 5 way speaker posts, removable power cord.

General Sound:
Big beautiful musical sound with little fatigue.

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

Reviews:
Click Here

Recommended Cables:

McIntosh Balanced Audio Cables (XLR)

McIntosh Audio Cables (RCA)

McIntosh Speaker Cables

McIntosh Power Control Cables

Kimber Kable - Ascent 10 Gauge Power Cord - Better 

Kimber Kable - Palladian 10 Gauge Power Cord - Best

Specs:
Power Output
Minimum sine wave continuous average power output per channel, both channels operating is:
75 watts into 2 ohm load
75 watts into 4 ohm load
75 watts into 8 ohm load

Rated Power Band
20Hz to 20,000Hz

Total Harmonic Distortion
Maximum Total Harmonic Distortion at any power level from 250 milliwatts to rated power output is: 0.5% for 2, 4 or 8 ohm loads

Frequency Response
+0, -0.5dB from 20Hz to 20,000Hz 
+0, -3dB from 10Hz to 50,000Hz

Sensitivity
Phono: 2.5mV for 2.5V rated output (0.5mV IHF) 
High Level: 250mV for 2.5V rated output (50mV IHF) 
Power Amplifier Input: 2.5V for rated output

A-Weighted Signal To Noise Ratio
Phono Input: 80dB below 10mV input
High Level: 93dB below rated output 
Power Amplifier: 100dB below rated output

Intermodulation Distortion
Maximum Intermodulation Distortion if instantaneous peak output does not exceed twice the rated output, for any combination of frequencies from 20Hz to 20,000Hz is: 0.5% for 2, 4 or 8 ohm loads

Input Impedance
Phono: 47K ohms, 65pF 
High: Level, 22K ohms

Maximum Input Signal
Phono: 90mV 
High Level: 8V

Preamplifier Maximum Voltage Output
Phono: 8V
High Level: 8V
Main Out: 8V at preamp output

Voltage Gain
High Level to Tape: 0dB 
High Level to Main: 20dB

Wide Band Damping Factor
Greater than 18

Power Requirements
US, 120 Volts, 50/60Hz at 3.6 amps

Preamplifier Tube Compliment
2 x 12AX7A Phono Circuitry 
2 x 12AX7A High Level Circuitry

Power Amplifier Tube Compliment
2 x 12AT7
4 x KT88/6550

Dimensions:
Overall Dimensions
Width is 17-3/4 inches (45.09cm)
Height is 10-1/8 inches (25.72cm) including feet
Depth is 18-3/4 inches (47.63cm) including the Front Panel and Knobs

Weight:
77 lbs.

Link to Manual:
Click Here

The SkyFi Testing Process for Preamplifiers:

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 PCB’s 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.

When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.

We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.

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.