plied to it is delivered to the load and hence none is turned to heat. This is because when it’s in its ‘on’ state, the switch will conduct all current but with no voltage across it, whereas when it is ‘off’ it will have the full supply volt-age standing across it, but no current flowing through it. In both these states zero heat is dissipated. Sadly, the world is not perfect and neither are these switches. That said though; efficiencies of over 90 percent are not unreal-istic. I should point out that the term “digital” is a little misleading because while the operation of the switches is controlled by digital circuits, the power stages are still dealing with voltage and current.

Moving to the physical design of 16-MR4.480 and to borrow a line from indepen-dent politician Rob Oakshott; “they’re ugly, but they’re beautiful in their ugliness”. One thing the 16-MR4.480 cannot be accused of is being good looking but there is something strangely appealing about their external aesthetics that makes you fall for their design. The entire outside of the amplifier is basically heat sink with chunky 7mm wide fins. This entire centre portion of the unit is metal which has been brush-finished and proudly sports a large blue backlit Memphis logo. The end caps are heavy duty shock resistant dark grey plastic and besides providing protection for the terminals and controls they also double as the mounting feet. On one end are the large power terminals in addition to the eight speaker wire outputs. Between these are two 20-ampere fuses. Turn-ing to the other end you’ll find the RCA inputs in addition to all the controls. These include switchable crossovers (LP/HP/FULL) and when

set to low-pass for subwoofers you have the option of 30Hz – 150Hz. If you’re running splits or coaxials and wish to high-pass them you can select between 50Hz – 180Hz. There is also a switchable bass boost at either 9dB or 18dB and, in our opinion, this control is of far less importance than, say, a phase switch or subsonic filter for ported boxes. Skillful compo-nent selection and installation would really make moot a bass boost control (much like loudness controls). Also absent is a speaker-level input. The overall foot print is very small measuring 250mm x 178mm, height is also small at 50mm and weight is not worth talking about being around two kilograms.

Internals and soundRemoving the bottom plate and having a dig around the internals reveals a well-made unit which still has a remarkable amount of room inside despite it being so small. You can thank the combination of expert design in conjunc-tion with digital switching for this reduction in real estate requirements. Component-wise; those within are quite good quality and attached to the fiberglass circuit board just behind the power input are the three caps that serve to smooth the voltage. From there current is stepped up via a large single air-core transformer and stored in a bank of eight power caps in the center of the unit.

When required, current flows to the tran-sistors which are attached and lined along the heatsink for maximum heat dissipation. Over in the far corner away from everything else is the sound processing portion of the circuit board and this section features, interestingly, resistors physically mounted diametrically opposed at 45 degrees. Sure it won’t make any difference to the performance but it makes for one interesting layout!

In the box you don’t get a great deal be-sides the amplifier itself, although Memphis do give you four mounting screws, washers and an Allen key. Finding a safe place to mount the 16-MR4.480 is a breeze due to the minute size requirements and it fitted under the seat in minutes. We then simply fed signal, remote and power cable to it and away we went.

Starting with the noise level test first with the engine off, we played the zero bit track on the test CD with the amp gain up to near full. The 16-MR4.480 is still pretty quiet even at full song. Sure it outputs a little hiss however, during every day operation, the gains should never be right up on any amplifier. If you need more power get a larger amplifier. Next was to set the gain correctly with a CRO and head out

for a listen. While the 16-MR4.480 is not the most stunning amplifier we’ve ever heard it is a very solid performer given its price and size. It is accurate when playing lightning fast and loud double bass drum beats and this is terri-tory when cheaper amplifiers tend to fall apart and start sounding like a blurred mess.

Likewise the highs were quite accurate and not harsh to the ears – to test this you need to know exactly how the song you’re listening to should sound, otherwise, you’re going to struggle because at volumes over 90dB ev-erything above 1kHz ‘can’ sound harsh to our ears – especially at their most sensitive region between 2kHz – 5kHz.

Playing more subtle music quietly and relaxing a little you start appreciating the quality of the unit– it doesn’t introduce ambient noise, like some other amplifiers are known to do, and overall it makes for quite a pleasant listening experience throughout the low to loud listening range. If you want to go from loud to extreme you may need to look at a more powerful amplifier because, as nice as the 16-MR4.480 is, it does have its limitations. If you’re an extreme volume listener you’re going to hit those limitations pretty quickly.

ConClusIonMemphis may not have quite the market share or advertising dollars of some other car audio behemoths but next time you’re in the search for a quality amplification upgrade, try to get yourself into a car equipped with a Memphis Reference amplifier. You won’t go wrong. Although relatively new to

Australia when compared to oth-er large car audio brands, in its

native country, the US, Memphis is a seasoned manufacturer. Truth be told; with over 40 years of experience in car audio ranging from early 4- and 8-track players through to modern digital switching amplifiers, Memphis has forgotten more about electronics than most other manufacturers will ever know. It’s for this reason that we’re always happy to test and review the Memphis gear whenever possible – because it’s quality gear at an affordable price.

The current rage in the audio market is digital switching full range amplifiers and, in reality, there are only a handful of companies that possess the technology to successfully produce these types of amplifiers. Memphis is one such brand but instead of rushing head-long into it like a bull at a cape, the company’s engineers instead took their time streamlining the new design to the point where the new

Memphis Reference range perform as well as any digital amplifier on the market, but they’re just a little superior in various areas – size being the most obvious.

small but bIgIn all honesty if it weren’t for the comparative-ly generous heatsink dimensions (in relation to the bare amplifier) the Memphis Refer-ence range would perhaps be the smallest amplifiers on the market for their given power output; period. There are five units making up the range including two single channels, a 2-channel unit and a 5-channel unit. Given that we’ve reviewed a few 5-channel ampli-fiers recently we instead opted to review the 4-channel 16-MR4.480 amplifier.

Starting with the bare basics; the 16-MR4.480 is a high power digital class-D design and each of its channels is rated at 80 watts continuous at 4-ohms. The birth certificate included with this particular unit stated that it had been tested to output 482 watts in total.

In other words it’s no powder puff but rather quite the angry ant. When presented with a 2-ohms load the channels output 120 watts each. So as far as performance specs go it may not be the epitome of high-power but they’re still very respectable. Total harmonic distortion is under 0.07 percent, signal-to-noise ratio is 79dB and overall frequency range is a realistic 20Hz – 20kHz. Sure it may not run up to 100kHz like some class-D amplifiers but then again you’re not shelling out the coin to entertain the neighborhood canines.

Just as a little background information; class-D amplifiers (sometimes called digital switching amplifiers) are a class of ampli-fier where the power devices (MOSFETs in the case of the 16-MR4.480) are operated as binary switches – by binary we mean either they’re fully on or fully off (i.e. 0 or 1). Ideally, this means they spend zero time transition-ing between those two states and therefore, in theory, they’re efficiency is 100%. In other words in a perfect world all the power sup-

More class-D Magic – just sMaller.

MeMphis 16-Mr4.480 aMplifier

• Stayslistenableatloudlevels• Wellmade• Canfitanywhere

• Canstruggleifpushed

“...there are only a hanDful of

coMpanies that possess the

technology to successfully

proDuce these types of aMplifiers.”

Orion’s XTR5004 is a tad up on price at $799 but offers a

class-A/B alternative

Focal’s Solid 4, in red or black, is justabout equally-powered and comes in

at a slightly lower price of $499

Type: Class-D 4/3/2 channel amplifier

power raTing: 4 x 80 watts at 4-ohms

(CES2006)

FeaTures: Adjustable crossover, bass-

boost (9dB/18dB)

CosT: $540

ConTaCT: Soundesign on 1300 862 289

web: www.soundesign.com.au

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SIGNIFICANT OTHERS

REvIEwER: M

ARTy PRICE

MeMphis auDio

16-Mr4.480 4-channel aMplifier

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