Fosi Audio BT20A Pro Bluetooth 5.0 Amplifier, 300W x2 Wireless Amp, TPA3255 2 Channel Mini Class D Integrated Home Audio Outdoor Stereo Receiver with Bass Treble Control for Passive Speakers

A nice little amp. Power consumption: With the supplied 32V 5A power supply, the unit consumes 1.7W while waiting for a signal and 3.7W when either bluetooth or RCA inputs are active. In normal use amp only pull about 3.7-4.0W - this is a big improvement over lots of my classic, older stereo gear that idles at 10-30W. It means I can leave it on 24/7 without worrying about the electricity bill and extra heat generated. I tried the 48V 5A power supply, and it seemed like it did make the sound a little tighter, especially in the bass. But, I did not control for volume so it's possible it was just louder. With the 48V supply, the unit draws 3W when waiting for signal and 7.8W with the output amplifiers on. With the 7.8W of idle consumption, the unit gets quite warm to the touch, and the consumption starts to approach more-featured receivers. I swapped back to the 32V power supply as I intend to run this near-24/7 so energy costs are important. Bluetooth sounds good and is my main use case for this system, but I'm not that picky. I haven't done super critical nearfield testing, but it sounds great filling a large room with a pair of old floorstanders. The two-band EQ is very useful, and is largely why I picked this particular amp. With my big old speakers it works great to tame the rumble a bit and add some sparkle back in. It's kind of annoying that the Treble knob is to the left of the Bass knob, which is backwards from basically every single other amp out there. That's only noticeable from up close though. Power and Gain: The amp's power is good. If you feed it a powerful signal the amp will give you more than enough volume. Bluetooth signal level is high and the RCA input is fine for anything modern that's mixed loud. I only checked for a few seconds but this amp gets way louder than I would ever need. The gain is just OK. I think it's pretty standard as far as amps go. It's still a little bit disappointing because it's hard to get a program with low signal level loud enough. It would be nice if there was a little more gain on tap or a low gain/ high gain switch. I'm debating getting a preamp to put in front of it. Overall I think it works great, looks great, and it's been powered on playing music pretty much 24/7 since I got it

I bought this amplifier to pair with my Sonos Port so I could use a set of Yamaha outdoor speakers, and it's been exactly what I was looking for. Setup was quick, and everything worked perfectly right out of the box. The sound is clean, powerful, and distortion-free, even when turning up the volume outdoors. I also like the compact design, it looks modern and doesn't take up much space in my media cabinet. I've had zero issues with it since installing it. If you're looking for an affordable amplifier to add passive speakers to a Sonos setup, I highly recommend this one.

Don’t be fooled by the size of this little giant. This unit packs a good punch despite its size. I paired it with a pair of Polk Audio Atrium 5 Outdoor Speakers, and it does a great job. There’s one extra feature that I love about this unit, which is the capability to connect to the audio system through Bluetooth. In my case I paired it with the Bluetooth of my TV and from it I can control the volume to the Fosi Amp. I am highly pleased with this little giant.

Years ago I purchased another FOSI amplifier. A fifty watt per channel one. Back then, even before I really knew much about class D amps, I thought it was an amazing little product. I am still using my original FOSI amp at a different location, and it has provided flawless service. Obviously now a fan of many Youtube audio channels, this BT20A Pro gets many accolades . With confidence I bought this one. I am using it in my garage, with ELAC OD-M81 speakers , and WiiM mini and now a SMSL D1 DAC. I am unbelievably happy with this system. I am running the tone controls flat, but did try them and they are not obnoxious is their adjustment. I like the metal case. The back speaker terminals are adequate if smaller, but no issues at this price point. I bought the one with the 32 volt power supply, and that is fine for my application, but am considering the 48 volt, just for the fun of it. And that last statement is key. This is fun!It's a solid little amplifier doing exactly what it is designed to do. Sound good, producing a balanced frequency signal and revealing the music as it was intended. As always, what you put in you get out. Older poor recordings will still be poor, but modern good recordings are excellent. This amplifier can be a part of an affordable, but excellent music system.

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.

I upgraded from the older BT20A, and this purchase was well worth it. The power output is so impressive that it actually led me to buy better speakers to match the performance. The amp’s compact size makes it easy to conceal on the patio, and setup was a snap; the speaker wire terminals were buttery smooth, even for someone with larger fingers. Bluetooth connectivity has been flawless, and I’m using the line-in feature with an old Echo Dot, which allows for convenient hands-free volume control. Highly recommended.

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.

We recently bought a new home, which was pre-wired in certain rooms, with in-wall Yamaha 8 ohm speakers, capable of decent sound. We simply wanted to be able to connect to the existing wired speakers, and push sound from our bluetooth devices. For the price, especially given this Fosi unit uses a Texas Instruments chip to not only push the quality sound, but to also protect the speakers, and balance the resistance, this was a great deal. It was about 1/2 of the pricier models that use junk chips and far too many "features," which not only raises the price on those models, but also doesn't (IMHO) deliver the quality sound this little Fosi unit does. It's tiny... like very tiny, and is a solid little piece, but seems well-built, as far as the case, dials, and bluetooth antenna. I like that it has RCA input plugs, if not using Bluetooth, but even more so, it has built-in female banana plugs for outputting sound to your speakers (in my case, to a 6-channel, non-powered splitter, that sends the signal from this little powerful amp to the speakers (not included). If using bare wire speakers, the banana plug inserts unscrew enough to slide and secure the bare wires in as an option. Very easy. At first glance (sound?) when I hooked it up, I was not so impressed. There are only 3 dials - Volume, bass and treble. And with the bass and treble neutral, the sound was unimpressive and tinny. I used music on my iPhone I know very well, so I could judge the quality of the sound being sent to the Yamaha speakers, which we'd already tested with another source initially, so we knew their basic quality was there. Upon turning the Fosi's bass dial to 100%, it filled in the music nicely and more warmly. It is in NO way thump or "bassy," rather, it just fills in the hollowness that was present with a neutral setting. The treble seemed fine at neutral. This is in no way an audiophile piece of equipment - not even close. But it does seem to be a step up over some of the other, more expensive brands that flood the market, but have numerous noted issues across multiple reviewers. This little Fosi unit weights a few ounces, is super easy to set up, and was alllmost immediately compatible with my phone's bluetooth, although it wouldn't show up in my bluetooth available menu at first. A quick Google check revealed that the very brief instructions (with its exceedingly small and annoying print) failed to mention HOW to cause the unit to pair via bluetooth. Turns out the volume button doubles as a reset/pairing command, simply by pushing in to click, then my phone immediately saw and very easily connected via Bluetooth. There is zero, and I mean zero hissing or buzzing when no music is playing, or it plays at low volume. Like NONE (which I'd read in numerous reviews, causing me to want to try this nice little unit). The controls are simply laid out, and it was immediately compatible with my phone - what more could you want? This isn't going to blow you away, but if you simply want decent, clean sound out of decent, quality speakers, especially via Bluetooth, this unit is amazing. It just won't be bumping and thumping, but the sound pushed to all 6 speakers is impressive. It does not have the ability to push a mono signal equally to all speakers, but for standard stereo music, it doesn't seem to matter - not the most powerful option, but for the price and quality, I'm quite satisfied, and it seems very well built and solid from what I can tell.

Get a set of used 8 or 10” tower speakers, connect this, Apple music.. enjoy! Heaven!

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

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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.

I am incredibly impressed with the Fosi Audio BT20A. Setting it up was an absolute breeze, taking only a few minutes from unboxing to playing music. It integrates seamlessly with my turntable setup, delivering clean, crisp, and punchy sound that breathes new life into my vinyl collection. The ability to switch over to Bluetooth streaming is a game-changer. The wireless connection is rock-solid, has great range, and makes it effortless to stream playlists straight from my phone. For its compact size and affordable price, the sound quality and power output are remarkable. It fits perfectly on my shelf without cluttering the space. If you need a reliable, budget-friendly amplifier that handles both classic analog vinyl and modern wireless streaming without any fuss, this is the one to get!