McIntosh MC501 Monoblock Power Amplifier  
Home Theater Power Amplifiers Mono Amplifiers
Written by Robert Mead   
Wednesday, 18 February 2009

As World War II was just ending, Frank McIntosh was starting up an audio company that would emerge as the benchmark audio manufacturer setting the bar for high-end audio components over the next 70 years. The performance level of Frank’s audio components was at such a high standard, even from its initial start-up, that television stations all over America sought out his mono tube power amplifier called the 50W-1 to be fully integrated into their television production facilities starting in 1949. The technology that powers that amp, the Unity Coupled Circuit, is still being used today.

The McIntosh line of high-end audio components only achieved further greatness when they started branching out into the consumer field in 1967 when their engineers designed their first solid-state product, the C24 preamplifier, which the early audiophiles of the 1960’s cleaned out their bank accounts to purchase. McIntosh was also the first audio manufacturer to implement the front-panel illumination that makes every power amplifier and integrated amplifier in the McIntosh line distinguish themselves from the also-rans in the audio world. The MC501 Power Amplifier is no exception to this rule. From the first time I set my eyes on this beauty, I was transfixed. I spent a good degree of time with the MC501 while visiting the “McIntosh Showroom” at my favorite home theater stores in the Las Vegas area, Premiere Home Entertainment .


The vice-president and co-owner of the store, Jim Wicklund, set up a demo in his main showroom and let me feast my eyes and ears on the ultimate audio-visual experience for any real audiophile/videophile worth his salt. The stainless steel chassis of this unit gleams at you while the watt meters lighting display shimmers with that pale blue light that McIntosh equipment seems able to integrate seamlessly into their entire line of power amplifiers and integrated amplifiers. There are two enormous knobs situated on either side of the amplifier, one for the meter control and the other for the power control which will let you use the remote to turn the unit on or off, based on your preference.

The MC501 is not small by any means. The height of this powerful beast is 10 inches high, by almost 18 inches deep and it weighs in at a plump 91.5 pounds. The price for just one unit will run you at least $4,100, $8,200/pair at most retail stores.  The back of the unit, which contains six transformers out in the open and with just minimal casing around them, looks like a work of sheer craftsmanship. The rest of the back of this unit contains nothing but stainless steel and a few connectors, nothing substantial. This adds to the overall design of the power amplifier, which seems to be going for a minimal design look, and when I say minimal I mean absolutely “bare bones.”  I find this kind of no frills design perfectly compliments a solid power amplifier.  The three sets of WBT binding posts complete the look of this power amplifier, and they are conformed for the Autoformer’s 2, 4 and 8 ohm outputs.

The RMS power output is rated at 500W minimum sine wave output from 20 Hz to 20 kHz, allowing for an unbalanced input impedance of 10,000 ohms, and balanced input impedance rated at around 20,000 ohms. This type of low impedance will of course insure that there will be no power line hum interfering with your audio system. McIntosh’s Power Guard has also been integrated into this unit so that clipping is prevented from destroying any high-end speakers in your configuration.

To go into a little bit more detail about the kind of technical precision McIntosh’s designers put into every one of their main circuit boards in their power amplifiers, I should mention that the MC501 is rated to deliver at well over 100 amperes of output current.  It also uses transformers (the Autoformer mentioned above) that load-match the amp in the output stage.  This allows the transistors to run cool and extend the life on the equipment.  The downside to this approach is that hot amps typically sound better from the consumer’s perspective.  There’s a definite trade-off of reduced audio fidelity for the sake of increased dependability.


The configuration for my demo of the MC501 at Premiere Home Entertainment was already set up in their main demo room to showcase a Marantz VP-15S1 1080p DLP  projector. The audio rack was lined with three MC501’s and one MC252 power amp. A Furman IT-Reference power conditioner was positioned directly underneath the Marantz BD8002 Blu Ray DVD player, with all the cable lines leading directly to the McIntosh MX136 Audio Visual Control Center which sent out the most precise and up-scaled video images to the Marantz projector and all the audio signals to the B&W Diamond 802 Series loudspeakers. These speakers had already been configured to the correct crossover frequencies by the Premiere home theater technician who has been certified as a McIntosh audio specialist after taking their technician’s test at the main McIntosh manufacturing plant located in up-state New York.

The MC501’s were all contained in the main rack to the left of the room and the speakers were all positioned on the opposite side of the room.  The main subwoofer was located to the left of the speakers, though I believe the subwoofer should almost always be centered under the movie screen for maximum impact. The dual McIntosh MC1.2KW’s were situated in the center instead. These two massive power amps push a huge 1,200 watts apiece, so giving them as much room as they needed was never a question, even at the expense of moving the subwoofer off to the side.  Another main component of this set-up was the McIntosh MX-136 audio-video processor. It can detect the exact surround codec while also ensuring that the best mode for the exact type of music/movie you are inputting into it is always selected; regardless of what you happen to be listening to.

The room itself is a well-insulated room that measured around 25 feet wide and 20 feet long, give or take a foot or two. The main speaker and cable wire used for this system comes from Kimber Kable, a speaker wire company well known for delivering impeccable sound to any loudspeaker system. The input sensitivity for the MC501 is rated at 2.1 volts unbalanced and 4.2 volts balanced, so the Furman power conditioner that was used in the main system’s audio rack ensured that the sound emanating from the power amplifier was as clean and concise as needed, while still providing plenty of power to drive the B&W Signature 802 Diamond Series loudspeakers.   The MC501 powers 500 watts into any audio system that handles between 8 and 2 ohms.  This set-up not only had one, but three of these power amplifiers driving the speakers, and I still didn’t discern any distortion whatsoever.

Movies and Music

To get the essential overview of what kind of substantial power three MC501’s can have on an elaborate home theater, I decided to start experienced that power by running the movie “I, Robot” after picking out the right seating arrangement in the showroom that would best demonstrate the power of the McIntosh amp.  The combination of the Marantz BD8002 Blu-ray player and the Marantz VP-15S1 DLP 1080p projector was also an excellent match and the digital audio steaming off the Marantz player impacted all the sound effects in the Will Smith movie with full and impressive clean dynamics. The movie screen I witnessed this action-packed film sequence on was a Stewart Filmscreen Firehawk G3 102-inch front projection screen, and the optical coating featured on this dynamic surface really brought out the image contrast and resolution of the Blu-ray version of “I, Robot.”

Jim cued up the action sequence in which Will Smith is driving along the freeway and the truck in front of him opens up its rear door where we see about forty or so robots ready to attack Smith at any second. The sub-woofer, which was aligned to the left of the screen, was able to handle the bass explosions as one of the main robots leaped onto Smith’s car with a huge crash and put his iron fist directly through the car’s windshield. Without question, the MC501’s powered this sequence with precision and clarity.  If you saw “I, Robot” in a THX-certified theater with an expansive amount of surround-sound speakers, you would still not have the sublime experience I had during this demo. When I heard the impact of the robot’s sheer iron fist going through that windshield, along with the soaring soundtrack that really enhanced the excitement level of that sequence, I was in cinematic heaven.

During this action sequence in “I, Robot”, you can hear Will Smith’s slightly panicked dialogue with crystal clear clarity, which means the MC501’s handles the delicate transition between bombastic sound effects and quiet dialog-heavy scenes. There was no time during watching this sequence in which the width of the sound elements dissipated at all. The mid-range from the B&W speakers always exploded with a definite clarity. The low-end bass sounds of Smith’s car careening all over the highway as he fought off the robot stuck on top of the hood of his car did not effect the MC501’s in any negative way whatsoever.  The orchestration on the movie soundtrack swelled to a high crescendo as the robot continued to hammer Smith’s now badly damaged car.  I could hear the cymbals clash with extreme clarity and the string section filled with violas, violins and the acoustic bass rushed through the sound system. I literally bent my neck back with the enveloping and powerful impact.

The sound effects emanating from the sound system really brought me headlong into the violence that was happening on screen. The sound of the glass shattering definitely sounded as natural as any sound effect I’ve ever heard, no matter the environment I was hearing it in. The chair I was in actually vibrated with the low-end bass that was being pushed out through the sub-woofer, and I was wondering if the MC501’s were going to be able to continually push the entire system to its limits without any distortion whatsoever. As the sequence ended, I had my doubts assuaged.

Another true test of a power amplifier is to see how a completely divergent soundstage plays out using that same power amp. To this extent, I listened to the digitally-remastered CD of Pink Floyd’s classic, “The Wall”, using the same Marantz BD8002 DVD/SACD player and running it to the McIntosh MX-136 A/V processor, but this time using the Aerial Acoustics series of floor-standing speakers instead of the B&W’s.  I used the same audio rack with the three MC501’s, but I went with the Aerial Acoustics to make sure that the MC501’s could capture “The Wall’s” quiet acoustic passages along with guitarist’s David Gilmour’s careening, sharp notes and his predilection for using echo effects to ensure the eeriness of his guitar’s overall tone during the album’s songs such as “Another Brick in the Wall” and the heart-achingly melancholy “Mother.”

I started my demo of “The Wall” with the aforementioned “Mother”.  The acoustic guitar strum at the beginning of that song shimmered with a brilliant lightness.  When Roger Waters’ vocals finally cut in, the showroom was filled with a vocal tone that just floated out to me as if by magic. “The Wall” is an extremely well engineered album, and the MC501’s powered the subtleties of this album by giving full power to the mid-range of the sound system that drives the vocals and keyboard sequences. The next song I listened to was the beautiful “Goodbye Blue Sky.” The beauty of this song is direct contrast to the Roger Waters almost suicidal lyrical content. This song also includes subtle sound effects that would be practically invisible to me had I not heard the song with the exact configuration highlighted in the Premiere Home Entertainment showroom.

The Downside

Although the MC501’s look extremely nice and pack a very powerful but clean punch to any home theater system, the power amp’s price of over $4100 for just one unit cannot be justified unless you absolutely need 500 watts of power distributed to your entire sound system.  Many consumers that are just looking to add more power to their audio systems don’t have a space in their homes so large that they need a 91 pound behemoth power amp to deliver the proper amount of clean wattage to their loudspeaker systems.  The bulk of the MC501 power amp also means that it’s not easily mounted on a simple audio rack and likely requires a rack capable of the weight.    


McIntosh has proven repeatedly that they are always on the cutting edge when it comes to designing and developing immaculate but powerful amplifiers, whether they are mono, 3-channel or integrated amplifiers. The sophisticated design of the MC501 delivers an aesthetic look that is second to none, while the clean power of the unit delivers a substantial thrust to every home theater system it is connected to. The fact that McIntosh audio equipment has a much longer life span than most other manufacturers speaks volumes about their reliability.  When it comes to the MC501 Monoblock Power Amplifier, the MC501 is a safe investment.


Special thanks goes to Premiere Home Entertainment, a Las Vegas based home entertainment company specializing in the design and installation of home theater, home automation, and home integration systems.  They are located at 2300 N. Rainbow Blvd., Suite 119 in Las Vegas. 

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