McIntosh MA2275 Tube Integrated Amplifier - Excellent Condition Collectors Set - Super Rare

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Standout Features:
• All Analog Tube Preamplifier, Phono Preamplifier, and Amplifier Sections
• 6 Total Inputs: 4 Unbalanced Inputs, 1 Balanced/Unbalanced Input, and 1 Moving-Magnet Phono Input
• Tape Recorder Loop
• Unique McIntosh Unity Coupled Output Circuit and Output Transformers for 2, 4, and 8 ohm speakers.
• Fiber-Optic Illuminated Output Wattmeters

General:
If you're looking for the coolest modern McIntosh integrated amplifier - this is the one.

We've only seen a handful of these come through the shop, and this the best condition MA2275 of them all.

The MA2275 is a sort of rare bird in the world of McIntosh for several reasons:

Very low production numbers and scarcity. At the time of writing this listing there are zero other units I could find listed for sale anywhere. Most of the MA2275's were sold in the Asian market where large integrated tube units were marketable.

This is the only ALL TUBE and ALL ANALOG 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.

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

Great reviews, check this one out for example.

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.

The MA2275 also features the famous McIntosh fiber-optic lighting on the VU meters giving them a very even glow. Plus you'll never have to worry about replacing any bulbs. 

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

This example is in excellent condition - the best MA2275 we've ever received into the shop.

Your collectors set purchase includes:
1) A complete factory fresh set of new McIntosh tubes - 10 total - all with the correct McIntosh silkscreening ($700).

The original tubes that arrived this with amplifier tested quite strong, but were not as balanced and matched as we would have liked.

So we replaced them all for the new owner. Then we tested all 10 new tubes in our modern professional Amplitrex AT-1000 tube tester to ensure they were performing as we wanted.

2) The original remote and also a new sealed current model HR093 replacement remote from McIntosh. The original remote on this model suffers from a tacky/sticking issue that is common with other remote controls from this era.

3) The original McIntosh owner's manual - not a reprinted copy.

4) The original McIntosh double-sided sales brochure / data sheet - not a reprinted copy/

5) The correct Service Manual for the serial # run of this MA2275 sourced directly from McIntosh Parts. Reprinted on heavyweight paper.

6) A new factory fresh official MA2275 McIntosh outer shipping carton along the original serial number stamped inner carton. Plus all the required interior packing materials

7) The original set of McIntosh furniture glides (QTY 4) that shipped with the MA2275 when new.

SkyFi Cosmetic Notes:
A few very small marks shown on the top of the unit in one area (front-facing right). Otherwise it is in excellent condition with just about zero signs of wear.

This era of McIntosh product uses a white silkscreen lettering on the chassis that can easily rub off during routine cleaning, leaving identifying text for the tubes and rear connects illegible.

Not so on this MA2275! It has the best silkscreening we've ever seen. We elected to very carefully clean around silkscreening where possible on the top chassis near the tubes to keep it this way for the new owner.

SkyFi Technical Notes:
Both channels tested to 85W per channel into 8 ohms with no issues or drama. All inputs and outputs tested on our test bench more than once, and this MA2275 moved to our listening area for several days to ensure there were no issues after replacing the full compliment of tubes.

Tube Notes: 
All 10 new tubes ordered from McIntosh were tested in our modern and professional Amplitrex AT-1000 tube tester.

Shipping:
This MA2275 will ship via truck freight anywhere within the lower 48 US States for a flat $500 which includes insurance for the full value. This freight charge will be automatically added during your checkout.

We can safely pack and palletize this MA2275 amps to ship worldwide, just contact us for a quote. Local pickup welcome and we can also arrange a local courier depending on distance. Please contact us for details. This item is exempt from any Free Shipping promotions.

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 and five way speaker binding posts

General Sound:
Big beautiful musical sound with little fatigue.

Cosmetic Condition:
9/10 = Excellent. Perfect physical condition, gently used. See our detailed rating description here.

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

Included:
See above "Your collectors set purchase includes" section for full details

Packing:
Original Manufacturers Packing

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 Complement
2 x 12AX7A Phono Circuitry
2 x 12AX7A High Level Circuitry

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

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.

Approximate Age:
2004

Link to Manual:
Click Here

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects

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 for Integrated 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 device has the ability to decouple the preamplifier from the power amplifier, we remove the jumpers and independently test each section. If the device cannot be decoupled, we assess the electronic condition of the piece by analyzing the speaker level output only.

We start by connecting the "Pre-Out" jacks of the integrated 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 1 KHz 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 1 KHz 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 section 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.

Next we test the power amplifier section by connecting the integrated amplifier speaker outputs 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 "Main In” jacks 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. 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.

If the preamp and power amp both pass these tests, we reconnect the sections and verify that the preamp section can drive the power amp to rated power with a 1KHz tone on one of the line level inputs.

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 moves 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.

SkyFi Testing Process - Specific to Tube Equipment:

We perform a full test of all of the tubes installed. We use a modern Amplitrex AT-1000 Professional Tube Tester which is capable of testing both emission and Gm with a high degree of accuracy. 

We document the results of each tube and replace any weak or suspect tubes before proceeding. 

When we power on tube amplifiers for the first time we usually use a variac and current limited AC supply and slowly raise the voltage up to nominal mains level while monitoring plate, screen, filament, and negative bias supply voltages where applicable.

If everything is in order we feed a low level test signal into the amplifier’s input and monitor its output on an oscilloscope across an 8 ohm dummy load. At this point we are just looking to verify basic function and confirm that the output transformers are not damaged.

Once we have verified that the amplifier is safe to operate, we connected it to full mains power. For fixed bias amps we set the bias to manufacturer spec. For cathode biased amps we monitor the plate to cathode voltage to determine if the output tubes are operating in a safe range. Once the output section is verified we move onto bench evaluation. 

We start by feeding the input of the amplifier with a low level 1 KHz test signal, slowly increasing its amplitude while monitoring the amplifier’s 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.

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. 

For tube amps we like to run this test at least twice.

This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when it has fully come up to temperature. We find this step to be essential, especially for vintage units.