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