What Is Class-D Amplification?STEREOS      SPEAKERS      SYSTEMS      AMPLIFIERS      ACCESSORIES      SPECIALS      HOW-TO INFO Video: How To Power A 12 Volt Stereo With Household Current Transcript:Marine stereos are designed to be used on Boats so they run off of 12 volt battery power. But what if you want to use a marine stereo in your hot tub, on your patio or by your pool and you need to be able to plug it into a wall socket?You will need a 12 volt power supply like this one that can adapt the power from your home to the type of power that your stereo can use.Not just any 12 volt adapter will do. These little power supplies that you commonly see, (I call them wall warts) are not going to do the job because they don't provide enough amperage. Most of these are less than 1 amp and that is just not enough.A typical stereo head unit will need about 5 amps of power. If you want to crank up the volume for parties and plan on using a powerful amplifier, then 5 amps likely won't be enough either.

We do have power supplies available that offer up to 30 amps.Some people will use computer power supplies and they work great. This 5 amp power supply that we sell works well, particularly because it has a rubber gasket that seals the case closed so water can't get in. That makes it good for use outdoors. water around ac unit furnaceTo connect this one to your stereo you just snip off the end and then splice the wires to the power wires in your wiring harness. split system air conditioner best pricesMost stereos have 2 power wires (one switched and one constant) and 1 ground wire. air conditioner split system inverterSplice both power wires to the positive wire of the power supply and the ground wire to the negative. Make sure you connect both power wires because it won't work with only one.

Plug in the power supply and you are good to go! Video: How Waterproof Is A Waterproof Speaker?Video: Satellite Radio On Your BoatVideo: Digital Compression And Your Marine StereoVideo: How Many Speakers Should I Connect To My Boat Stereo?Video: Wiring Speakers To Your Marine AmplifierThere's cheap, and then there's dirt cheap -- and we'd throw the Lepai LP-2020A+ into that latter category. That's due in part to its no-name brand provenance; indeed, we've never heard of the (presumably Chinese) manufacturer before, and the name seems to draw a blank on Google. Available online at sites such as Amazon and Parts Express for less than $25, this mini amplifier is something of a throwback to the days of component stereos and shelf-top audio systems. The product is literally just an amplifier: you provide the line-level audio source (a smartphone, a CD player, a cable box, a PC, whatever) and the speakers, and the Lepai handles amplification duties. The result is nothing you wouldn't get from an integrated boombox or shelf-top stereo, nor anything that's outstanding enough to tempt serious audiophiles or anyone with top-quality speakers.

But the LP-2020A+ has a certain old-school charm, and lets you pick your own speakers. If you accept its limitations, this little amplifier's sound may actually exceed the expectations of most buyers. With its low, low price I expected that the LP-2020A+ stereo amplifier would be tiny, and it is -- just 1.5 inches tall by 5.5 inches wide by 4.5 inches deep. Since the amp weighs less than 1 pound, it's likely to slide around on your shelf whenever you touch it, but the cutouts in the metal flanges on the sides of the chassis can be used to secure the LP-2020A+ to a wood shelf. It's an effective, if low-tech, solution to the amp's tendency to move around when you adjust the controls. The Lepai LP-2020A+ is predictably no-frills, but we were happy to see the tone (bass and treble) controls. For this kind of money you might expect the amp would be a little plastic box, but no, the LP-2020A+ has an all-metal chassis and faceplate. The smoothly turning volume control doesn't feel cheap, but the very bright backlit blue LED ring surrounding the volume knob might be downright annoying in dimly lit rooms.

The front panel also has bass and treble tone control knobs, and a Tone/Direct button that turns the tone controls on and off. The Lepai has two sets of stereo inputs on the rear panel: one 3.5mm minijack and one set of RCA (red/white) jacks. Note that the LP-2020A+ doesn't have an input selector. The RCA and 3.5mm inputs are both on all the time, so if, for example, you had your TV and iPod hooked up and turned on at the same time you would hear both of them over the speakers connected to the amp. That's no big deal -- just turn on only the source you want to listen to. Alternatively, if you're using a PC as one of the inputs, you may well appreciate the always-on inputs, since you'll be able to hear the computer's alert sounds mixed in with the second audio source. The Lepai's rear panel has 2 inputs, plus the requisite speaker wire clips. The rear panel also has two sets of spring clips for connecting speaker wire. To be clear, there's no line-out or headphone jack, so you'll need to connect a standard set of speakers.

Powered speakers (such as PC speakers) won't work, and they'd make the Lepai amp redundant, anyway. The amplifier's TA2020 amp chip incorporates Tripath's proprietary Class-T Digital Power Processing technology. This chip was cited by the engineering magazine IEEE Spectrum as one of the chips that "shook the world" when it was introduced in 1998. No wonder Tripath amplifiers have earned a reputation for sound quality from budget-minded audiophiles, and the LP-2020A+'s rich tonal balance won't tarnish that impression. Looking over the comments on Amazon's customer review pages, it seems there's some confusion as to whether the LP-2020A+ comes with an AC power supply (a small wall wart), but the two models we ordered (from Parts Express and Amazon) both did. While the review sample of the amp looks the same as other Lepai LP-2020A+s sold on the Internet, its long and flat cardboard box looks very different from the glossy box with a picture of the amp on the box I've seen from other vendors.