|Monster MPA 5150 Multi-channel Power Amplifier|
|Home Theater Power Amplifiers Multi-Channel Amplifiers|
|Written by Brian Kahn|
|Sunday, 01 July 2007|
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The ever-present Monster Cable brand is expanding. Not a company to rest on its laurels, Monster’s vast portfolio of products will now include power amplifiers to go along with a robust offering of cables, accessories, furniture, speakers and beyond. Monster power amplifiers, like their recently reviewed loudspeakers, are not being prominently promoted on their own, but rather as part of an entire Monster products solution. One day you will be able to walk into a Monster Cable M Design dealer and purchase an entire Monster system.
The Signature MPA 5150 five-channel reference power amplifier ($3,500) is one of three amplifiers in the Monster Power amplifier lineup. The MPA 5150 is a five-channel amplifier rated at 150 watts per channel into eight ohms and 250 watts per channel into four ohms. The MPA 5150 chassis is anything but your ordinary black box amplifier. The styling is consistent with Monster’s line of power conditioners. The 75-pound, 17-inch-wide by 20.25-inch-deep and seven-inch-high chassis, with the exception of the front panel, is made of a heavy gauge black metal. Much of the body is perforated to increase cooling.
The front panel aesthetics are unlike those of any other amplifier I have seen. Detachable rack ears flank a five-section, brushed silver aluminum front panel that is reminiscent of five leather-bound volumes on a bookshelf. Each of the five sections has an oval LCD window in the top section. Below the LCD window are two LEDs, vertically stacked. Finally, there is a retractable knob halfway down the panel. The center section also features two buttons, the discs of which appear to be made out of the same material as the front panel. Each of the LCD windows is a power meter. These are reputed to be laboratory grade digital power meters that will depict the actual wattage being used by each channel. The meters have a peak hold feature. The LEDs depict power and clipping; the potentiometers are for input sensitivity. The center mounted buttons are for power and a 12-position brightness control. The back panel is not as fancy as the front panel, but it is similarly full-featured with balanced inputs, unbalanced inputs, a switch to select between them and five-way binding posts for each channel, IEC power receptacle, grounding pin, voltage selection switch, main and channel fuses, remote on/off input and output. Build quality is topnotch and the amplifier is as solid as they get.
The MPA 5150 is not only full-featured, it comes with everything that one would need to get the amplifier installed in your system, with the exception of audio cables, which of course Monster will be happy to sell you. Inside the box, in addition to the amplifier, I found all the hardware necessary to rack mount the amplifier, a comprehensive owner’s manual, remote power cable and DC power transformer (to act as a remote trigger if there is no other trigger in the system).
The MPA 5150’s guts are substantial as well. Even though Monster Cable has plenty of smart engineers and designers on staff, they were wise enough to employ the services of someone with a great deal of experience in the world of amplifier design. The amplifier was designed by Richard Marsh, a name well known in audiophile circles in connection with power amplifier design. Twin transformers and power supplies insure that the amplifier can exceed its power specifications, even with all channels driven. Peak power output is over 500 watts per channel into four ohms and the amplifier is stable below two ohms. The signal to noise ratio is greater than 113dB A weighted, THD <.01 percent at 1kHz, <.02 percent at 20kHz at rated power into eight ohms. Speaking with Mr. Marsh about the amplifier, it became clear that the MPA-5150 is a high-current design and that the specifications are extremely conservative. There is much more power on tap than 150 watts per channel while keeping within the above performance specifications.
Mr. Marsh and I discussed the amplifier’s design and he explained the Monster Mirrored Amplifier Technology (MMAT), a current feedback circuit topology that is said to lower distortion and increase clarity by mirroring the input signal at the output stage through fully complimentary differential circuits. A balanced, complimentary push-pull stage is reported to be ultra-wide bandwidth to take full advantage of today’s 192kHz recordings. Mr. Marsh feels that it is important for amplifiers to be able to reproduce these higher frequencies for superior soundstaging. High-current MOSFET output transistors permit quick, high-current transfer for increased dynamic capabilities.
The Monster MPA-5150 was quite simple to set up in both my reference stereo and theater systems. In my stereo system, I utilized my Krell KAV-400xi and McIntosh Laboratories C-220 as preamplifiers, with the Krell driving the 5150 through its single-ended inputs and the McIntosh through the balanced inputs. I used B&W DM604S3, Krell LAT2000 and Monster’s own THX towers for speakers in my two-channel system.
I used the balanced inputs of the MPA-5150 when it was installed in my theater system, driven by the balanced outputs of the Halcro SSP100 and Krell HTS 7.1 processors. The speakers utilized in my theater system with Monster Cables MPA-5150 included Dynaudio’s Audience series speakers and Monster THX Select speakers. The binding posts, like the rest of the amplifier, were sturdy and solid. I had no problems connecting all the cables to the MPA-5150. While each channel had its own individual level control, my speakers were close enough in sensitivity that any level adjustments were easily handled by my processors.