Seems like every time you turn around these days, you hear the term “efficiency.” We’re living in an age of making everything we use more efficient, whether it’s a light bulb, a home appliance, or our cars. You don’t have to be a rocket scientist to figure out that efficiency is a good thing, especially when it doesn’t come at the price of performance. If someone would have told me back in 1980, that one day I could buy
a brand new car that has 400 horsepower and gets 25mpg, I would have thought they had a short circuit between the headphones. You might as well have tried to achieve time travel too! The technology available in 1980 simply wasn’t good enough. But here we are in 2010, and lo and behold, there are quite a few new cars that can do just that, or better!
Well, efficiency is a good thing when it comes to car stereos too! And while most people are familiar with the full-power efficiency advantages that Class D amps have had in the past, this oft quoted spec is only a very small part of the efficiency equation. What good does an amplifier that is 80% efficient at full power do when you are typically only using a small fraction of that power? What most folks don’t realize is that the vast majority of car audio enthusiasts, even those who tend to play their system a bit louder than anyone else, are seldom actually using more than 10 or 20 watts of power! And while a good Class D subwoofer amp may be 80% efficient at its full power of say 500 or 1,000 watts, it’s still only about 15-20% efficient at the volume levels it gets used at most of the time.
Here’s where the guys at Arc Audio come into the picture. Avid readers of the magazine may recall that Arc Audio had been producing some high efficiency Class G amplifiers for a couple of years now. Well, they have surpassed the efficiency even of Class G, with the all new XXD series of full range Class D amplifiers. And more importantly, these new amplifiers are exceptionally efficient at fractional power levels, which means they’ll draw less current, and generate less heat, all the time!
To let me check it out for myself, Arc Audio sent over one of their brand new XXD 4080 4 channel models. The amplifier has a small footprint, measuring about 10.5” x 7” x 1.8” tall. The Arc Audio XXD 4080 is a good looking amplifier, it is covered in smooth surfaces, and rounded corners. There are no traditional “fins” on the heatsink, and the top of the amplifier is almost completely covered with a gloss black acrylic panel. In the center of the top panel, the Arc Audio logo lights up in a pale blue when the amp is powered on. Each end of the amplifier is populated with the usual connections and controls, power, speaker and a pair of 20A ATC fuses are found on one end, while panel mount style RCA inputs, and all signal adjustments are found on the opposite end. I did note all of the wire connections use the same 2.5mm hex driver, so a single tool is all that’s required to make the connections. Attention to little details like this simply make life in the install bay a bit happier, and I’d be remiss not to point out the Arc Audio teams efforts in that area. On the control side of things, there are fully independent crossovers for front and rear channels, with the high pass section having a range of adjustment from 65Hz to 250Hz, and the low pass filter range is a bit wider, in this case from 50 to 250Hz. Each set of channels also has a three position Bass Boost switch, labeled 0, +6, and +12dB. There is also a blue power-on LED on this same end panel.
Inside, there are built-in under and over voltage protection circuits, as well as protection for thermal and short circuit conditions.
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