Marantz MM8003 Power Amplifier 
Home Theater Power Amplifiers Multi-Channel Amplifiers
Written by Brian Kahn   
Monday, 01 December 2008

When I first heard that the MM8003, the companion piece to Marantz’s new audio/video processor, the recently reviewed AV8003, was going to be a 8 channel amplifier I thought it was kind of strange. Now that it is here I see that the 8 channel idea was well thought out. A 8 channel amplifier can power an entire 7.1 system with a passive amplifier such as those found in many in-wall systems; four separate stereo systems; a 5.1 system with the left, center and right speakers bi-amped or the mostly likely use, powering a 5.1 system in one zone and a stereo system in another zone.

Each of the MM8003’s 8 channels is rated at 140 watts with less than .08 percent total harmonic distortion with a signal to noise ratio of 105dB. The power supply providing the juice for all of this is includes a multiple-secondary toroidal transformer rated at 600VA and 100,000 microfarads worth of custom-designed capacitors. The capacitors are mounted on copper-plated, anti-vibration brackets. Many of the key components are from well respected manufacturers of audiophile grade components such as WIMA. The amplifier’s topology includes the use of current feedback. The current feedback topology is said to improve the amplifier’s operating stability while letting it react to quickly changing signals across a wide frequency range. A close look at the MM8003 reveals that much of its design, including the LAPT Hyper Power devices come from the highly regarded PM-11 Reference Series Stereo amplifier.

Looking inside the 17 3/8 inch wide, 7 5/16 inch high and 15 1/8 inch deep (shallow enough for just about any equipment cabinet or rack), 39.5 pound chassis you will find that a lot of careful thought went into the design of this piece. The rear section of the amplifier contains a Wilson current mirror circuit said to amplify sounds with minimal distortion, the rear portion of the amplifier also contains the LAPT high-performance power transistor. Copper bus bars are used to bring power to each channel, the power supplies are carefully crafted using a laminated core, silicon steel-plated core ring. Extensive shielding is also present to protect the details crucial to an amplifier’s ability to reproduce ambiance. A variable speed fan and chimney style heatsink construction make for a durable, long lasting power supply. All of this is housed in a rugged steel and copper chassis that features an aluminum and glass-resin front panel that mirrors the contours of the AV8003. The rear panel features single-ended and balanced inputs for each of the 8 channels, each channel has a switch to choose the active input and a high quality binding post for the speaker connections. The rear panel also features an ungrounded IEC style power connection, a switched outlet, flasher input, DC and remote control inputs and outputs. All this can be yours for the very reasonable price of $2,399.

Even though the majority of people purchasing this amplifier will be using it in multi-channel systems before I placed the MM8003 in my multi-channel system I placed it in my stereo system. In my stereo system the MM8003 took the place of the Halcro DM38 which costs more than eight times as much with one quarter the number of channels. The pre-amplifier was Conrad Johnson’s excellent CT-5. CD’s were played back on the Classe CDP-202 CD player. I switched between Kimber Select and Transparent Ultra single ended interconnects and speaker cables. The power cable for the amplifier was a Kimber Palladian PK-10.

The multi-channel system I used with the MM8003 featured its companion piece that I had just finished reviewing, the AV8003 preamp/processor. The MM8003 replaced Halcro’s MC70 which retails for about three times the price of the MM8003. The sources I used with the AV8003 include the following: Marantz DV-9600 universal disc player; Halcro EC800 DVD Player, and a Sony PS3 (for Blu-ray). I used Kimber Cable for all audio, video and power cabling, taking advantage of the ability to run balanced interconnects between the AV8003 and MM8003. Speakers were MartinLogan Summit and Stage speakers for my main and center speakers, respectively. I also used a complete set of Acoustic Zen Adagio’s with the full size Adagio’s for the mains and the Adagio, Jr.’s for center and rears. The Adagio’s were particularly helpful in reviewing the MM8003’s bass capabilities as the Summit’s have powered woofers but the Adagio’s relied solely on the MM8003.

Listening to the MM8003
I let the MM8003 break in for a few days and then on the first day of listening I let the system warm up for a couple of hours before sitting down. I began with Dire Strait’s “Money for Nothing” from Brothers In Arms (Warner Brothers). I find the opening guitar riff to be a good test piece. The Marantz was able to reproduce this fast paced piece with sufficient detail for me to easily discern its details. The dynamics and sense of rhythm were good and sounded much better than the amplifier in any of the audio/video receivers I have heard recently, another point in favor of separates. At the highest listening levels I noticed a slight bit of compression in dynamics but there was none at any normal listening levels. Vocals of Mark Knopfler and Sting were reproduced with the right amount of grit and chestiness that I have come to expect. There was no lack of detail that hid the individual characteristics of these voices.

Paula Cole’s song “Tiger” from her album This Fire (Warner Brothers) always provides  sonic workout. Cole’s vocals were sweet and warm. The soundstage width was comparable to the big Halcro in width but not depth in the detail of placement. While the eight times more expensive Halcro was better across the board, it should be. However, the Marantz was impressive as well. The Summits are incredibly revealing speakers that are easily capable of discerning sonic gaffs of any of the upstream electronics. There were no sonic gaffs to speak of with the MM8003. The Marantz was extremely clean and detailed throughout the frequency range with only the occasional slightest hint of solid state grain or glare. No weird harmonics, unusual harshness, distortion, etc. So how does the Marantz MM8003 differ from the uber amplifiers of the world? The Halcro and Krell amplifiers in my system brought the level of refinement up, more detail in the nuances, more power etc. For example, when listening to “Tiger” through the Acoustic Zen Adagio’s the high ends had more ambiance through the Halcro and Krell. The explosive bass notes of this track were also reproduced with more authority. At moderately loud volumes the Marantz had no problems driving the 6 ohm Adagio’s, however at house shaking levels the larger Krell and Halcro amplifiers could go further with no signs of dynamic compression. As a practical matter, this will rarely come up with most systems, especially if you are able to bi-amp your speakers. (The Adagio’s only have a single set of binding posts.)

Multi-channel music was handled with equal aplomb by the Marantz without any shift in sonic character. Diana Krall’s album Love Scenes (GRP/DTS) provides a chance for a multi-channel amplifier to show its ability to portray its musicality across all channels rather than just being a test of brute force. The track “Peel Me A Grape” is dripping with Krall’s sultry voice and is pure sensual bliss. The Marantz let Krall’s sultry voice shine through, the critical midrange had vocals that were warm and full with detailed and delicate backing instrumentals. The disc uses all five channels to reproduce the ambiance of the hall with good success. Listening to the album with the Marantz providing the power I had no problems closing my eyes and picturing myself there.

Stepping it up a notch (or quite a few) and bridging the gap to movies, I moved to concert videos. Specifically, the Godsmack concert video “Changes” (Zoe Records). I was turned on to this piece during a Marantz demonstration so I figured it was highly appropriate for use here. “Batalla de los Tambores” is one of the most visceral and dynamic tracks I have heard in a long time. This battle between the two sets of drums is fast and furious. The drums featured a mix of deep throbbing beats with quicker hits off of the snare drums providing a good workout for any multi-channel system. I listened to this piece through the Adagio system. The notes were all reproduced with great accuracy and detail, I could close my eyes and tell who was hitting what without difficulty. However, closing my eyes was difficult as I found myself feeling as though I was there and kept opening my eyes to make sure I wasn’t going to be trampled in the mosh pit, truly an involving experience with a heightened sense of realism. It wasn’t just that that powerful onstage notes were reproduced realistically, but that the rear channels provided sufficient detailed information to place me inside the concert hall. What more could I ask for from an amplifier? Well, perhaps a bit more power so I could push the envelope even a little bit more. When the family was gone and I cranked my system up to insane levels there was a bit of compression and a slight loss of dynamic slam.

Finally, we get to movies. “I Am Legend” (Warner Home Entertainment, Blu-ray)  provided many different sonic tests. There are many delicate nuances in this film, the way voices change when Will Smith’s character moves into different environments, such as inside to outside, the decay of the echo of rifle shots, etc. The MM8003 had no problem rendering any of this with ease. The mass evacuation scenes and the later interior fight scenes also provided the Marantz the opportunity to show off its resolving power in all channels yet with increased dynamics, again it was done with ease and good sense of involvement. Dynamics, the backbone of any action flick must also be reproduced well to keep the illusion real. Without giving away the plot, there are several scenes with explosions, animals and other dynamic sonic tracks, no matter how many channels were involved the Marantz had plenty of power to handle it while keeping the sounds discrete, detailed and realistic. Dogs, sounded like dogs, gunshots like gunshots, etc.

I watched several more movies, including “Cloverfield” (Paramount, Blu-ray), which I had just used in the review of the AV8003. This movie features a battle scene in the beginning with deep and powerful bass notes as buildings come slamming to the ground while crowds, alarms and more blared from every direction. Again, the Marantz had no difficulty whatsoever discerning details from every channel while maintaining the proper dynamic balance. No matter what I through at this amplifier it was quick, detailed and neutral.

The Downside
Within the limits of its performance envelope, there is little to fault with the MM8003’s sonic abilities. It doesn’t have the same black background or level of nuanced detail as the world’s uber-amplifiers but it performed much better than I expect and amplifier to do at this price point. With respect to absolute bass performance, most people will use a powered subwoofer, but if you are going to use a passive subwoofer I would try to audition the amplifier with your subwoofer, in your room (a good idea with any audio purchase) to make sure it can provide you with the power and control desired at the lower reaches. The Marantz worked well with the highly damped and tight, Adagio woofers but many of the passive subwoofers aren’t so tight and need an iron fist to control them.

I would have liked to been able to internally bridge channels. For example, with demanding music at high volumes the Adagio’s could have used a bit more power but I could not bi-amp them. As I was only using five channels, it would have been nice to bridge six of the channels to provide for three more powerful front channels.

Lastly, the resin front panels. While they look nice, match the cosmetics of the AV8003 and show that the company is not wasting money on expensive front panels that do not contribute to sonic performance, I received a few comments from visiting audio/video enthusiasts that they expect a metal front panel at this level. Personally, I place my amplifiers in a rack and it doesn’t bother me in the slightest.

Like the recently reviewed AV8003, the MM8003 provides great bang-for the-buck. Like the last Marantz amplifiers I had the pleasure of listening to, the MA500 mono-blocks (discontinued for several years), the MM8003 continues the tradition of musicality and value. This amplifier may not be the end all when if comes to microdynamics (although detail is extremely good) or iron fisted bass at full volume, within its limits it performs extremely well and its limits should be broad enough to encompass most systems.

What draws me most to this amplifier is its sense of involvement, it has a good sense of rhythm and pace while remaining neutral, reproducing vocals and instruments in an organic, non-mechanical way. I never confused it for a tubed amplifier but it didn’t exhibit any of the pitfalls of solid state amplifiers usually found at this price point. The Marantz performed well with stereo sources and was outstanding on multi-channel material. No matter how hectic the soundtrack got, each channel was reproduced without compromise in performance. I have no reservations recommending this amplifier for theater systems in small to moderately sized rooms (or larger rooms with 5.1 systems that have bi-ampable front speakers.
Manufacturer Marantz
Model MM8003 Power Amplifier
Reviewer Brian Kahn

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