There'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.
Design and features
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.
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 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. A 6-inch-long adapter cable with a 3.5mm plug at one end and stereo RCA connectors at the other is included with the amplifier. Amazon's customer review pages also report occasional quality control problems with the LP-2020A+, but both of our review samples worked perfectly well.