A new generation of inexpensive mini Stereo Amplifier has made it possible to put together a stereo speaker system for about the same price as you’d pay for a good wireless speaker. Whether you’re building a system for your desktop, den, or dorm, we think the Fosi Audio BT20A is the best way to get started in affordable stereo sound. Combined with a good set of bookshelf speakers, the BT20A can deliver sound quality that even audio enthusiasts will respect.
Fosi Audio BT20A Stereo Amplifier
For those who crave affordability but fear compromise, the Fosi Audio BT20A is the ideal mini stereo amplifier, thanks to its combination of power and features. Even though it’s less than 4 inches wide, it was one of the most powerful amps we tested—powerful enough to drive large tower speakers and to play deep bass tones without strain. The BT20A includes Bluetooth support for easy wireless connection to phones and tablets, as well as bass and treble controls that let you fine-tune the sound to your liking. Standard RCA jacks and a Bluetooth/auxiliary input switch allow for simple hookup and operation. The only real downside is that it looks and feels a little cheap.
The Fosi Audio BT20A makes it possible to set up a good-sounding stereo system for the price of a mid-level Bluetooth speaker. The BT20A is only about one-thirtieth the size of a typical stereo receiver, yet it delivers clear sound even when driving large speakers at volumes loud enough to drive most people out of the room. It’s bass and treble controls let you fine-tune the sound to your liking, and its onboard Bluetooth support allows you to connect wirelessly to phones and tablets with no extra hardware or cables required.
The BT20A is one of the two most powerful mini amps we tested (the other being the Topping MX3). Although that didn’t make a difference when I was listening to moderate levels, I could easily hear the difference when I cranked up the volume. When I played the deep bass notes of Lil Baby’s “Sum 2 Prove” (video) and Holly Cole’s version of “Train Song” (video) at a maximum volume of about 100 dB (similar to the level of the rumble you’d hear on the platform when a train pulls into a station), the BT20A was one of only two mini amps (the other being our runner-up, the Loxjie A10) that didn’t distort or shut themselves off. Even when playing loud through the $3,500 Revel tower speakers, the BT20A sounded clear and strong, with little or no audible distortion, clear vocals, and enough bass to get my chair shaking a bit.
The tone controls on the BT20A are a nice plus, especially if you use the amp with cheap speakers that might need some fine-tuning. My measurements showed that the range of these controls is +6/-7 dB for the treble and +10/-16 dB for the bass, which is plenty for you to get the level of the bass just right for your room or to make harsh-sounding recordings sound a little smoother.
Loxjie A10 Stereo Amplifier
When it comes to looks, the Loxjie A10 is the most distinctive mini amp we’ve seen, especially the red version (it’s also available in black). In addition, the A10 is one of the best-performing amps we tested: It was not quite as powerful as the Fosi BT20A, but it was still able to drive large, expensive tower speakers to loud levels, and we slightly preferred the quality of its sound. Its only potential downsides are its lack of Bluetooth support and tone controls, as well as its utter inability to escape visitors’ attention.
The Loxjie A10 is appealing in the same way as many products designed by Philippe Starck—it’s barely recognizable for what it is, but its radical design actually increases its functionality. The A10 is one of the more powerful mini amps we tested, and it’s the only one of these amps that seemed to sound better than the others (although only by a smidgen). It doesn’t include Bluetooth support or tone controls, but if you just need a basic amplifier, it’s a superb choice.
In two blind tests, each against three different mini amps, the A10 was the only one of these amplifiers I singled out for sounding a little better than its peers. To me, it sounded slightly more robust and vivid than the other amps, regardless of whether I played it loud or soft, and voices sounded a little less lispy and sibilant through the A10. The A10 also maintained its composure when I played deep-bass material at about 100 dB, producing clean, chair-vibrating bass tones from the Revel tower speakers.
The slim, 2¼-inch-wide design of the A10 makes it easier to fit on a desktop or bookshelf. The A10 has the same miniature speaker-cable binding posts as on the Fosi Audio BT20A, but here they’re spaced farther apart, which makes it easier for you to connect the speaker cables and also permits the use of dual banana plugs. The amp uses a pair of RCA jacks for the audio input, and the only controls are a volume knob and a power button on the front. The A10 is available in a red-anodized or black-matte finish.
Douk Audio Tone Stereo Amplifier
Measuring less than 3½ inches wide and offering more features than in many high-end integrated amplifiers, all at a surprisingly low price, the Douk Audio Tone is an exceptional bargain. In our tests, it didn’t sound as clear at high volume levels as our other picks, but it has enough power for a bedroom or desktop system. The features are the main attraction, as it provides Bluetooth support, RCA and 3.5 mm analog inputs, a USB digital input, a headphone jack, sturdy speaker-cable binding posts, and a cool-looking front LED power meter.
The Douk Audio Tone is one of the smallest and least expensive mini Stereo Amplifier we tested, but it has the most features of any under-$100 amp we found, and it performs well for its size and cost. Although it didn’t sound quite as clear and powerful as our other picks when pressed to its limits, it did prove more than adequate to drive our large tower speakers to a satisfying (but not extreme) volume. It also includes Bluetooth support, a headphone jack, and extra analog and digital inputs, and its front power meter is an attention-getting touch.
At normal listening volumes—loud enough that a listener can focus on the music, but not so loud that it drives everyone else out of the house—the Tone sounds similar to our other picks, to the point where few listeners would likely note any difference, much less one worth caring about. The only difference worth noting is that voices can sound subtly coarser, as if the singer had just spent a minute in a smoky bar. When I played hip-hop and jazz recordings with deep bass at about 100 dB, the Tone distorted the sound more than our other picks. Unless you have large speakers with big woofers, or want to play your system loud enough to drown out power-tool noise in the garage, it should work fine.
The Tone’s chassis is extremely compact at just 3 7/16 inches wide, so it takes up very little space on a desktop or shelf. The volume control doubles as a push-button input selector; its position on the top of the Stereo Amplifier is especially convenient for desktop use. On the rear panel, you’ll find a set of standard RCA analog input jacks, while the front panel adds a 3.5 mm headphone jack and a 3.5 mm analog mini-jack, plus a USB Micro-B digital audio input for use with computers, phones, and tablets. The amp is available in black or blue, and the Amazon product page also shows a silver version, though we couldn’t find that version for sale.
The front LED power meter is a cool touch; it makes the Tone feel more like a “real” audio component. Two meters are on the front, but they show the same signal level at all times, so it’s actually a dual-mono meter rather than a stereo meter. Considering that the meter is there for ornamentation rather than utility, we’ll forgive this.
While the Tone has a lightweight, plastic chassis, it uses sturdy, metal speaker-cable binding posts spaced to accept single or dual banana plugs, with wire holes big enough to accommodate heavy-gauge cables. Not that the Stereo Amplifier requires such cables, but if they’re all you have on hand, this is a nice convenience.
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How we picked Stereo Amplifier
Mini Stereo Amplifier are marketed under numerous brands, some of which appear to be owned by the same company, and we often see the same model marketed under multiple brands. Many of these amps look similar, and many use the same Texas Instruments amplifier chip.
In a category where new models pop up like mushrooms after a winter rainstorm, and where so many amps appear only to be slight variants of other amps, it’s impossible to do a comprehensive review. So we simply scoured Amazon and Parts Express to find the most promising and interesting models.
The criteria we used to decide which amps to test included the following:
- Power ratings: This is the first spec most people consider when buying an amp. We considered amps of all power ratings because our early tests showed that even those with the weakest power ratings were adequate for typical home listening levels.
- Power supply: We tested only those amps that included power supply. Most mini amps come with a “lump in the line” power supply, but some do not, requiring you to purchase a generic power supply such as those used for standalone computer hard drives. We figured a few people would want to spend time searching for one.
- Duplicate products: We didn’t test what appeared to be the same amp under different brand names. For example, we didn’t test both the Lepai LP-2020TI and the Lepy LP-2020A.
- Features: Although we did test some amps that had only a volume control, we gravitated toward models that offered nice extras such as Bluetooth support and tone controls.
- Design: The popularity of the industrial-looking Lepai amps made them a must for this test, but even so we favored amps that would look okay on a living-room bookshelf.
- Price: We set a rough limit of $140, which let us include a couple of full-featured models from S.M.S.L. and Topping. Above that price, most amps can’t be considered “mini.”
We tested 10 Stereo Amplifier: the Douk Audio G5 and Douk Audio Tone, the Facmogu F900 and S800, the Fosi Audio BT20A, the Lepai LP-168HA and LP-2020TI, the Loxjie A10, the S.M.S.L. SA300, and the Topping MX3. Although we took pains to get in all the biggest names in mini Stereo Amplifier, this test group represents a highly subjective sample of what we thought might interest readers. If there are other models you’re curious about, drop us a note in the comments.
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How we tested Stereo Amplifier
It’s common to see reviewers wax eloquently about the differences in sound among amplifiers, but as research has shown, most of these differences disappear when the testing is blind. Making this a blind test was challenging because, due to the COVID-19 pandemic, I wasn’t able to recruit additional listeners, thus I had to serve as both the test administrator and the subject. Fortunately, I have a speaker switcher I designed for blind tests, along with a Behringer Ultralink DS2800 distribution amplifier. By labeling the inputs on the switcher and distribution amp only by number, and by jumbling up the wires so that I didn’t know which amp was assigned to which number, I was able to set up tests in which I didn’t know which Stereo Amplifier I was hearing until after I had made my judgments and traced the connections.
I used a voltmeter and a 1-kilohertz test tone (video) to get the output of the amplifiers matched to within ±0.1 decibel, a difference too small for the human ear to detect. This is critical to fair testing because if one Stereo Amplifier is only slightly louder than the others, the listener is likely to prefer it.
I sourced all my test material from a PC laptop with a Focusrite Scarlett 2i2 USB audio interface, which let me access music from Spotify and Qobuz, as well as test tones stored on the computer. For speakers, I alternated between using the ELAC Debut 2.0 B6.2 (one of our picks for the best bookshelf speaker, which typically sells for $350 per pair) and the Revel Performa3 F206 (a tower speaker costing $3,500 per pair). The subtle differences I heard among these amplifiers were audible through both speakers, but the F206’s greater bass capability and power handling let me push the mini amps too—and sometimes even past—their limits.