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The Fosi Audio BT20A Pro is a compact, high-efficiency Class D amplifier delivering 300W per channel with Bluetooth 5.0 wireless connectivity. Featuring the TI TPA3255 chip and customizable bass/treble controls, it supports swappable Op-Amps for tailored sound profiles. Ideal for both indoor and outdoor passive speaker setups, it combines audiophile-grade performance with user-friendly features and low power consumption.















| ASIN | B07JVFY27T |
| Best Sellers Rank | #2,081 in Electronics ( See Top 100 in Electronics ) #4 in Audio Component Amplifiers |
| Brand | Fosi Audio |
| Built-In Media | BT20A Pro Bluetooth Amplifier x1, 32V 5A Power Adapter x1, User Manual x1 |
| Customer Reviews | 4.5 out of 5 stars 2,662 Reviews |
| Item Weight | 547 Grams |
| Manufacturer | Fosi Audio |
| Mfr Part Number | BT20A Pro |
| Model Number | BT20A PRO |
| Unit Count | 1.0 Count |
P**R
Amazing Clean Powerful Streaming
I admit that I have little knowledge of audio And electronics. I thought 300 watts of audio power had to come from a big heavy expensive amp. My new house came with 8 ceiling speakers . I had no idea whether they worked or sounded decent. The previous owner left an AVX speaker selector next to a bunch of speaker wires that were coming out of a wall port. I called Cambridge Audio and an advisor told me I would need to buy an amp costing at least $600 to run the speakers. Since I had no idea how it would sound , i looked on Amazon for an alternative. I took a chance on this tiny inexpensive Fosi amp to see if the setup even worked. It turns out that 3 of the 4 zones work and each sounds great using my phones Bluetooth and Apple Music through the Fosi into the speaker selector . I am being cautious with this setup , but I have determined that I can definitely power three zones simultaneously at rockin’ volume. The bass is not earth shaking , but is ok. I am amazed at the sound . Since the speaker selector has an impedance protector switch, I am relatively certain that I will be able to run 3 zones simultaneously without blowing out the speakers. I think the Fosi Amp is great . I am not audiophile and have reasonable expectations. The amp has an 18 month warranty. It is tiny and the Bluetooth is so strong that I do not have to leave my phone next to the amp. I highly recommend this tiny Bluetooth amp.
R**M
A (super pleasantly) Surprising Little Amp with a Ton of Power and Terrific Sound
This is an absolutely terrific little tiny amp. I cannot attest to the actual wattage of this unit but I can share that this has a nice amount of power and headroom for such a small amp. I am using it in my basement workshop. It is connected to a pair of old Boston Acoustic 2-way bookshelf speakers and an EverSolo DMP-A6 as source. I never turn the Fosi up beyond 10 o’clock on the volume and usually run it around 8-9. The sound is crisp. The dynamics are tremendous. It has breathed new life into a very old pair of speakers and with the Eversolor A6, it is a modern streaming config. The amp is literally a fraction of the size of my EverSolo, thus it fits virtually anywhere. It gets only somewhat warm at most and this is after running it for hours. I absolutely love this little guy and could see so many different uses for it: an outdoor audio set up, a garage set up, heck, you probably could drive some efficient floor standing speakers with this thing. I strongly recommend this if you want a tiny amp with terrific tone controls and power. The sound is simply crisp, precise, powerful… surprising (and I own several pricey, proper audio rigs in my home).
J**R
Excellent Amplifier, excellent sound quality
i have a lot of Fosi audio amps, this one,, sound incredible.. but i go to the next step and i buy the Fosi Audio 48v 5A powersupply... and i will give you my impressions about this powersupply and this amp. i recommend this amplifier... This power supply proved to be an outstanding choice, effortlessly driving my pair of high impedance speakers while delivering impeccable performance. With its reliability, robust build, and impressive capabilities, this power supply exceeded all my expectations. Performance and Compatibility: The 48V 5A power supply flawlessly powered my high impedance speakers, showcasing its exceptional performance capabilities. The impressive voltage output and ample current supply effortlessly met the demands of my amplifier, resulting in clear and dynamic sound reproduction. The power supply consistently delivered a clean and stable power signal, ensuring a distortion-free audio experience. Its compatibility with high impedance speakers allowed me to unlock their true potential, revealing nuanced details and captivating clarity that brought my music collection to life. Reliability and Build Quality: One of the standout features of this power supply is its remarkable reliability. From the moment I connected it to my amplifier, I experienced uninterrupted power delivery and consistent performance. The sturdy build and high-quality components instilled confidence, assuring me of its long-term durability. Additionally, the power supply's efficient cooling system prevented overheating, even during extended listening sessions, which further demonstrated its reliability under demanding conditions. Versatility and Safety: I appreciate the versatility this power supply offers. Its 48V output combined with a 5A current rating make it suitable for a range of audio systems, not just limited to high impedance speakers. Furthermore, the power supply incorporates several safety features, including short-circuit protection and overvoltage safeguards, ensuring the protection of my valuable audio equipment. Conclusion: In conclusion, the 48V 5A power supply has proven to be an exceptional choice for powering high impedance speakers. Its superior performance, reliability, and compatibility with a wide range of audio systems make it a standout option. Whether you're a casual listener or an avid audiophile, this power supply will undoubtedly enhance your audio experience.
S**E
Brought My Old Speakers Back to Life
Picked this up to run a pair of old Cerwin-Vega RE series speakers from the 90s, and it worked out great. It’s got plenty of power to drive them and they still sound awesome. The Bluetooth makes it super easy to stream music without dragging out a full AV setup, which is exactly what I was trying to avoid. Setup was simple, and once it was hooked up, it just worked. No messing around, no headaches. It’s also nice not having a big receiver taking up space—this keeps things clean and minimal. Overall, great little amp that makes old speakers useful again without all the extra clutter.
N**O
Great Value Mini Amp—If You Know What to Expect from Class D
Before purchasing this mini amplifier, I thoroughly researched user reviews on Amazon and expert opinions on YouTube to make an informed decision. Most Amazon reviews were positive, though a few two- or three-star ratings with concerning experiences gave me some hesitation. I was already familiar with the sonic characteristics of Class D amplifiers—often described as clear, detailed, and analytical, yet somewhat lean—which aligned with my experience using a 15-year-old Pioneer Elite Class D HT receiver. After purchasing the amp, I tested it with both Bluetooth and CD sources. Overall, I’m satisfied. Bluetooth playback was clear and more than adequate, while CD playback—paired with a small external DAC I also purchased on Amazon—sounded excellent. As expected, the amp delivers a clear, detailed sound signature typical of Class D designs, though slightly on the analytical side. I use this amp in my small study with vintage Mission bookshelf speakers, and the sound quality surpasses that of my previous Denon mini stereo amp. I listen to a variety of music, including acoustic, vocal, jazz, standard pop, and classic rock, and this mini amp–bookshelf speaker combo delivers a satisfying listening experience across genres. Female vocals can occasionally sound slightly elevated in pitch, but this can be adjusted to some extent using the tone controls. Most jazz vocals and instruments retain their nuance, though the overall sound leans toward a slightly analytical and bright tonal character—typical of Class D amplification. Despite this, the amp handles jazz and pop with clarity and energy, making it a solid choice for casual listening. Given its affordable price, this mini amp is a great option for anyone seeking budget-friendly performance in a small to medium-sized room. Unless you're a critical audiophile, there's no need to spend hundreds of dollars on a Wiim amp or high-end DAC. For casual music enjoyment, this amp offers exceptional value.
T**T
Punches far above its price point
The Fosi Audio BT20A Pro is an exceptionally capable compact Class-D amplifier built around the well-regarded TI TPA3255 chip. It delivers clean, low-distortion output with excellent channel separation, tight bass control, and a neutral tonal balance that pairs well with a wide range of passive speakers. The noise floor is impressively low for this price class, making it suitable for nearfield listening and revealing speaker setups. Power delivery is robust, with strong dynamic headroom when paired with an appropriate PSU, and the bass/treble tone controls are implemented transparently without introducing obvious coloration when set flat. Bluetooth connectivity is stable with minimal compression artifacts, while the RCA input maintains solid signal integrity for wired sources. Overall, the BT20A Pro offers impressive technical performance and efficiency in a minimalist form factor — a strong value choice for budget-conscious audiophiles seeking clean power and flexibility.
K**Y
Shockingly Good Little Amp — Perfect Drop-In Replacement for an Outdoor BBQ-Island Setup
I bought this little gray superhero after my previous “mystery box” amplifier (buried deep inside my outdoor BBQ island like some kind of archaeological artifact) decided to cut in and out every time I turned the music up past “mellow backyard vibes.” Nothing kills a good afternoon faster than your speakers crackling like they’re coughing up dust. 📦 First Impressions This thing is tiny. Like “did they ship me the right item?” tiny. But don’t let the size fool you — it punches like a heavyweight. Bluetooth range? Strong. Power? More than enough to drive the 6.5” Aquatic AV outdoor speakers I already had wired in. 🔧 Installation (AKA: How I Crawled Into My BBQ Island and Survived) My previous setup looked like NASA mission control. Wires, harnesses, proprietary connectors, and something pretending to be a subwoofer box. The Fosi made the whole thing simple: • Speaker wire → into left & right terminals • Power adapter → plug • Bluetooth → connect • Music → immediate happiness No proprietary weirdness. No random 4-pin blue plug. No tears. 🎵 Sound Quality Compared to my old Aquatic AV amp, which acted like it had seasonal allergies, the BT20A Pro is clean, strong, and shockingly loud for its size. • Bass is smooth (especially with your speakers’ built-in low-end) • Highs are crisp • Mids are clean • And the bass/treble knobs actually do something instead of just pretending Honestly, for a backyard setup that sits in a protected cabinet, this little thing is the perfect “sweet spot.” 📡 Bluetooth Fast pairing. Zero drama. I walked almost to the front yard before it even hinted at disconnecting — which, for anyone with an outdoor entertainment setup, is basically sorcery. 🔥 The Verdict If you want: ✔ A simple, clean replacement for a dead factory amp ✔ Power that actually moves your outdoor speakers ✔ Bluetooth that doesn’t quit ✔ A device that you can install without needing an engineering degree ✔ Something small enough to hide anywhere …then this is exactly the amp you want. 😂 Bonus Humor Section My old amp weighed 10 pounds and sounded like it had asthma. This Fosi weighs nothing, and sounds like it drinks pre-workout. ⸻ ⭐ Bottom Line: For the price, size, and performance, this little amp is the MVP of my backyard. If Fosi ever makes a “Pro Plus Ultra Nuclear Edition,” I’ll be first in line — but until then, this thing is staying right where it is, working flawlessly while I grill, chill, and pretend I’m an audio engineer.
R**E
Remarkably Good
I listen to vinyl on a Audio-technica AT-LP60x run through a good Phono Box MM pre amp through Klipsch Reference R-50M bookshelf speakers. All decent components. For the past two years I have been powering with an Aiyima T9 Pro with upgrade GE 5654w tubes. With the upgrade total cost apprx $200.00. I think it sounds great. I have been looking for a small D Class amp to also run. I was excited to get one that came out in March that cost $299.00. Audiophile...maybe. Anemic. I sent it back. Anyway, I browse a lot while I'm listening to music and started to read reviews about this Fossi BT20APro. I had some Amazon points so I figured I'd give it a try, not knowing really what to expect. It arrived overnight. It has banana plugs and uses the same power source as my Aiyima so the hook up took seconds. I turned it on and let it sit for a couple hours. I put on Waxahatchee's latest album and it sounded good. I then gave it a rest and turned it on the next morning. It is now putting out wonderful sound. I have played all my reference albums: White City by Pete Townsend, Heavy Weather by Weather Report, Aja By Steely Dan, New Sensations by Lou Reed, and of course the Beatles Sgt Pepper. The Fossi, with the eqs both set flat, 12 o clock, produced the sound of the alums remarkably well. Deep bass. Punchy Mids. Clear highs. A well defined sound stage. It sounds better than a stock Aiyima and compares very favorably with the tube upgraded unit that I use. There are some slight idiosyncratic differences, probably because of the tubes, but I find both sounds to be pleasing. They both make my Klipsch speakers come alive and produce a full range of sound. I am very happy with my old school set up to listen to vinyl. I am keeping both these small amps. It only takes seconds to switch them. The total cost for the both of them is under $300.00. What's not to like.
L**Z
Great sound, easy to install
The device sounds great and is easy to install. An additional digital USB input would be helpful for PC output. The knobs are too close together for comfort. I bought my second device now. It's the perfect solution for computer output or streaming to your loudspeakers. However, there is room for improvement: 1) There is enough space on the front plate to have more distance between the knobs. It's easier to turn the knobs if your fingers fit between the knobs. 2) I have to bend to see what the bass and treble knob are. The description would be more convenient on top of the knobs instead of being hidden beneath them. 3) The analogue-to-digital converter in your PC might be of low quality. A digital USB-C input could improve the quality and would be very convenient. 4) Earphones can skip forward and backward through your music list. You could add this functionality by pressing the bass and treble knobs respectively.
A**B
Fosi BT20A PRO - Small yet bombastic 👍👌🇮🇳🇮🇳🇮🇳
This is a honest review of FOSI BT20A PRO. After trying a few Inexpensive yet good class D amps, I decided to go for the fosi bt20a pro, as its based on Tpa3255 and has the bluetooth & rca connection options (till 6.months back there were too few BT amps from fosi or aiyima) Here is my review Build : Pretty solid, everything is upto the mark, the aluminium used high grade anodised one, no creaks and squeaks anywhere when you hold the amp. All the three knobs (bass treble and Volume) are sturdy but somehow the one I got had a kinna wobbly volume knob, dunno if it's just me or this is the way it is. The back connectors and sockets are placed pretty close to each other but with some small maneuvering everything can be pushed, tied and fixed. Accessories There comes a bluetooth antenna the standard one & decent enough, which you have to add yourself. POWER SUPPLY : the amp is rated to work from 24v to 48v power supply but is shipped with a Fosi branded 32V 5A one.. It does what is expected of it and the output is sufficient..(at lest fir my use case scenario is more than enough) The wire provided with the power supply adapter is of adequate length, the block and wires all look decent and feel study enough . Checked its voltage and it does produce what is claimed 32.4V to 32.5V. Functionality.. Bluetooth connects in a jiffy and the coverage is good. Kinna tricky sometimes to get the connection changed but by and large it's easy to switch from BT to RCA There is also a socket of 3.5mm pre out at the back which can be used to supply signals to an active subwoofer which is awesome in my view... But I don't think I ll ever need that because the amp giving enough thump already with the pair or my Sony passive speakers. This same socket can be used to connect this amplifier as a preamp to another amplifier if you want.. ONE VERY IMPORTANT THING : The amp comes with replaceable op amp chips, (which require the user to remove the screws and slide out the motherboard and then chnage the op amp chips) the more enthusiastic audiophiles who like to experiment with different sound signatures can change them according to their preference.. FOSI has suggested a number of op amp chips that one can try after purchasing them from market or from online.. (there a few available at Amazon India as well) In my personal view it is sounding pretty good as it is so for majority of users there is absolutely no need to experiment with the op amp chips. Audio quality Please note I use my SONY BOOKSHELF SPEAKERS with this.. The one which came with my Az2d music system they have a kind of plasticky cone hence the bass is pretty tight and I love that. Via Bluetooth it sounded pretty decent (please note I use Spotify with highest streaming audio quality on an iPhone) Through RCA I stream via my Google chromecast audio and the sound is fantastic. Over all its pretty loud, the tone knobs do a good job and the best part is there is a neutral point for both bass and Treble exactly in the center so you get a good reference point.. The low freq response is awesome which is genuinely deep and tight, the high freq are pretty good too but may be a bit more wanting like 10% lesser than the bass response... But that's just me... Over all it has played everything nicely that I have thrown at it... Mids are pretty good ( as you are to manage the mids via your preamp etc, you can further enhance them as well) Be it the jazz, or Bollywood music, or ghazals by Mehdi Hassan and Live Indian Classical renditions in both vocal and instrumental, it played everything nicely (of course you have to adjust the knobs according to the type of music as well as the source quality) Edit : after using for more than a month I can say the sound is pretty neutral and with a wide stage, the high frequencies need a tad extra kick for my liking so I am trying to arrange a preamp now to boost the quality further.. But one thing is for sure, via Google chromecast audio (which technically means that there is a proper DAC before the RCA input (as the GCA has a dedicated DAC in it) this thing just sounds so great.. Please note : type of drivers (speakers) plays another huge role so please use atleast half decent ones with these... All in all I am pretty happy, would have loved a fully functional remote and a knob to manage the mids too (I know that's tricky) Would have loved to have couple of more connectivity options like optical etc but I know I will never use them so doesn't matter, but having them would have been great even if just for academic purposes... In the end I can safely say that its a pretty good small package Would highly recommend it as tpa3255 chip perfoms extremely well and with its implementation on the fosi board it produces very loud audio without much distortion... There is no hissing or clicking when the amp is idle and it doesn't get hot (that much) as well.. Thanks
M**Ş
Tavsiye ederim.
Ürünü fiyatına göre değerlendirmenin daha doğru olacağı kanısındayım. Dali Oberon 3 ile kullanıyorum. Boyutuna göre, gerek detay, gerek bas ve tiz performansı olarak memnunum. Hızlı ve sorunsuz teslimat için Amazon'a teşekkürler.
A**E
Best customer support
It seems that I got a particularly broken unit, in which the Bluetooth module caused an annoying crackling and buzzing sounds. The manufacturer's support team was simply professional and I was positively surprised by the level of understanding and support I received.
D**Y
Buena opción economica
Estuve comparando diferentes amplificadores de clase D para conectarlas a unas bocinas polk de exterior, entre ellos Nobsound y Dual, en alternativa a comprar un SMSL ya que sus precios son más elevados. Su tamaño compacto me pareció muy conveniente para su fácil almacenamiento, en comparación a otros como el Dual que es mas grande y voluminoso. Leyendo reseñas y viendo diferentes criticas de youtube me decidí por este amplificador Fosi, vi que un problema recurrente era la pobre conexión vía bluetooth, por lo que de antemano decidí comprar un adaptador para esta función, se puede conectar por los puertos RCA o por AUX. Probé la antena bluetooth que trae el producto y no me pareció mal si solo quieres tener un dispositivo conectado, pero si como yo, buscas que sea fácil cambiar entre dispositivos para reproducir audio y tener un rango mas amplio de conexión, te recomiendo comprar un adaptador multidispositivo con mas alcance. La calidad del sonido es muy buena, se puede apreciar bastante bien el sonido y tienes 3 controles para hacer modificaciones. Los controles de bajos y altos, hacen un buen trabajo pero nada excepcional, lo cual es aceptable por el precio del producto.
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