Fosi Audio Bluetooth Subwoofer Amplifier 2.1, BT30D Pro Subwoofer Amp with TPA3255 Chips 165W x2+350W & Bass Treble Control, 2.1 Channel Sub Amplifier for Desktop/Outdoor/Bookshelf Speakers

So for people reading this thinking why the glowing review, let me tell you first what my main system is. My speakers are B&W Nautilus 804’s with Nautilus 800 HTM 1 center, 805 surrounds and SVS height speakers for Dolby Atmos powered by a Denon AVR-X4700H. This amp and speakers in no way compares nor could it.For my computer, I bought a Cambridge Soundworks package containing The BassCube 821 and the MC 105 speakers about 13+ years ago. The BassCube has a down firing 6.5” polypropylene woofer (4 ohm) in a sealed box that also contained the amplifier for the three speaker system. The MC 105 (8 ohm) has a 1” aluminum dome tweeter with a 3” midrange in a sealed cabinet. The system was similar in design and appearance to the Klipsch ProMedia 2.1. Unfortunately, my system finally failed after years of service leaving me searching for a suitable replacement for that particular location and purpose. What failed was the amplifier that powered all 3 speakers. The power supply filter caps failed taking out components down line – not worth fixing.I considered the Klipsch ProMedia 2.1 but the long wait time and some reviews mentioning early failures and sound issues made me hesitant. My next choice was the Edifier S350DB which is larger than the Klipsch and my Cambridge system and it too had it’s detractors and is $400. So, I tried the Fosi Audio Bluetooth Subwoofer Amplifier 2.1, BT30D Pro and was blown away by the sound. Connecting it to the MC 105’s was easy as I just needed good speaker cable with with banana plugs at one end for the amp and twisted wire for the speakers. The 6.5” subwoofer speaker I connected internally directly to the existing speaker terminals. I first removed the wires from the internal amp and used two of the four speaker terminals on the back to connect the woofer to the sub input on the Fosi. Then I put all the screws back into the back panel of the subwoofer to close it making a good air tight seal.Previously, the bass coming from the BassCube 821 when it worked was boomy at times and sloppy it wasn’t tight and certainly didn’t go deep. Now it feels tightly controlled, musical and it goes way deeper. It seems to have more synergy with the MC 105’s which also sound more musical to the point that I actually listen to music while working on the computer instead of watching TV. Your mileage may vary based on the speakers you use but at this price point for me at least it was worth the try and I am amazed/surprised at the audible results. The amp has just the right settings to tailor the sound to your speakers and preference. The separate Bass and Treble are mainly for the smaller speakers and have little effect on the subwoofer. For the sub you have SUB FREQ which sets the cutoff point from deep bass going clockwise on up and SUB VOL which together give the ability to tailor the sound to your liking.I bought a power strip that turns on the monitor and the amp when the computer powers up so I don’t have switch it on and off, the TrickleStar TS1104 7 Outlet APS, 1080 Joules, 3 ft Cord White sold on Amazon https://www.amazon.com/TrickleStar-TS1104-Outlet-1080-Joules/dp/B0B61ZCPK6.Now when I turn on the computer everything turns on by itself, the amp and the monitor.So if you have a dead Cambridge or Klipsch system and are handy with a soldering iron or if you have speakers you really like but their current amplification is not so great, give these a try, you might be pleasantly surprised.BTW, I have received nothing in return for this review.All the best:ArtIf you found the review helpful, give me a thumbs up - Thanks!

This thing is awesome! I do recommend getting the more powerful adapter for it if you’re running big speakers like I am. I have it hooked up to a 8 inch ds18 subwoofer and 6.5 inch component speakers with their own crossovers. IT GETS LOUD!!!!! I’m amazed how this little amp can power this subwoofer. I can feel it in my chest when I stand close to it. And it’s crystal clear sound when turned up. Hands down worth every penny! Easy set up. No problems at all.

I can't say enough nice things about this amp. Smooth knob turns, no clicking. Great sub frequency cross-over selection and volume controls. Also love the bass and treble controls. If this product had the option to turn off the Bluetooth I would have bought more of them. Small, compact and plenty of power. I'm using it to drive Left and Right speakers and 2x12 inch subs. the 12s are overkill but the box is left over from college so finally putting it to good use. Bluetooth works great, just wish I could switch it off so I could use more units in other places without having to worry about some stranger connecting to it.

I've been using this amp for 6 months on my PC, first just plugging it into an RCA to 3.5mm audio out, then plugging it to the Fosi K5 Pro (that one's still a story in progress, has some issues but they don't matter to the amp).This amp can very easily and comfortably drive a pair of JBL Control 25AV and JBL Control 1 speakers. No clipping, no distortion, just pure sound with the knob at 50%. For small speakers like that, it is very good. I did not try the Subwoofer output, i actually bought it thinking i'd need a sub with my speaker setup, but both speakers have very nice bass already, and i'm not that much of a bass head so i will be skipping the sub. The BT connection is very nice, although i had to rig my own BT antenna since the one that came with the unit offered too much range. Still, it is always better to have more than to have less, and BT is easy to adapt to a shorter antenna run, so i had no issues with it. The unit definitely gets hot to the touch, but never too hot that it burns me (i can place my hand on the top and feel it is warm), and it is not like it would even get to start a fire if you put something plastic on top of it (i put my Kindle on top of it by accident and left it there for 3 hours and neither the amp nor the Kindle showed any damage). And i got this unit with a very nice 20% discount coupon, so for under $100, this amp is really awesome.Now, for the cons. If you have big-ish speakers, you will definitely need more juice. I tried this amp to a pair of Pioneer CS-503, a pair of speakers rated for 50w @ 8Ω as per the label on the back (and as per Fosi's power table, this amp should be good enough for them on the stock power supply) but are really big beasts, and this amp definitely sounded less powerful on them. Still no major issues, but it sounds like this could use a bigger power supply. On that front, it came stock with a 32V 5 A power supply... and that's a really big mistake, since the voltage range is really small. This unit can only accept up to 36v power supplies, while most other amps from Fosi take up to 48v power supplies. This amp should come stock with the bigger power supply, especially since i doubtr the same 32v 5A power supply could deliver the same quality if i added a sub to it. And to make things worse, the 36v power brick is not even sold by Fosi! They sell 32v and 48v, but no 36v, so unless you get a random power brick, there's no way to juice up this amp. Lastly, having only automatic BT selection can be annoying if you already are listening to the RCA input. It happens to me when i turn on my laptop, it auto latches on the BT and my PC gets silent until i can disconnect it again on my laptop. It is a relatively minor annoyance, but when it happens at least once a day for 6 months, there's no way to even ignore it. Having a BT selection switch/button would be a great help for this.Overall, if you get this amp for under $100, it is a steal for small to mid-size speakers. And the fact that it accepts both RCA and BT inputs makes it extremely versatile. However, there are definitely better options if you need more juice, don't need a subwoofer, or want more control. Fosi makes some other excellent amps, and other brands too, but for $100-110, this amp definitely loses to those other options as other options do deliver better audio quality, are cheaper or can accept a bigger power supply for more oomph.