Nobsound Mini Bluetooth 5.0 Power Amplifier, Stereo Hi-Fi Digital Amp 2.0 Channel 50W×2 with AUX/USB/Bluetooth Input, Wireless Audio Receiver, PC Sound Card with Power Supply (Black)

The reviews that claim this is "unbelievable for the size and cost" are rather... apocryphal.That said for a USB DAC, I would definitely say it's fairly decent, and overall does a good job.I use this to drive some 160W Pioneer reflex loudspeakers and it does a good job; I have this amp at 1/4 on the volume dial and that's plenty enough for room easy listening, with little noticeable distortion and no obvious clipping. The connectors on the back work with both spliced cables or banana plugs; I did reuse some existing decent audio cables and it's comical how they drag the small lightweight amp down.I do have some cons though:- By default the unit seems to enter Bluetooth mode (blue status led) and I need to unplug/replug the USB cable for it to switch back to USB (green status led).- Mode changes are accompanied by an absolutely unnecessary "USB mode" or "Bluetooth mode" announcement via the speakers. I wish this could be turned off as it's wholly unnecessary to hear when I power up my system.- When the USB plug is connected and the laptop source is not issuing any sound, there's a clear white noise hiss coming out of the speakers. It is _very_ noticeable. That does not happen in BT mode. So let that sink a bit: in USB mode, there's a clear *analog* white noise hiss when there's no USB signal... That leads me to believe they don't turn the amp off even though the USB is not providing any data. That white noise is present in the "quiet" sections of music too.- I tried to use it in BT mode and there's a clear noticeable delay, at least 250 ms or more. It's significant enough that I can't watch a movie with that in BT mode.- The power supply is fairly light and never seems to get too hot. Probably the typical buck converter design. It would not be a bad idea to put these behind a power strip and cut power completely when you're done.Bottom line : The sound is acceptable for what costs a fraction of a proper USB DAC. However the BT/USB switch and the mode announcements are real turns off.

I am somewhat of an audio enthusiast and let me start by saying that this is one incredible and powerful little amp. I've recently completed a rebuild of some Polk Audio 6.5" outdoor speakers and bought this amplifier to power them. Let me tell you, the sound level is truly amazing. This amp really has some muscle and the sound quality is quite good. I did, however, have a slight issue and need to apologize to Douk Audio. I had a replacement unit sent to me due to Bluetooth audio dropouts and severe distortion. I thought I had a defective unit, but the replacement had the same problem. Come to find out, the problem is with my iphone 6. The iOS was recently updated to 10.3.2 and it ruined the phone's Bluetooth connectivity when connected via wifi. All of my Bluetooth devices now have audio playback issues. The Nobsound's Bluetooth function does work perfectly with my other tablets and wife's iphone 6 which has iOS 10.2.The build quality seems pretty solid and I do like the fact that it accepts banana plugs. So far, the longest continuous playback has been about 1.5 hours and the amp only has gotten moderately warm playing at mid to low volume. I will be putting it through the paces soon. I plan on taking it to the beach along with my outdoor Polks that I previously mentioned. I'll be using a 12ah SLA battery with a 150W inverter for power. I've tested the set up and it works pretty well. I estimate the battery should last about 6hours using the supplied 5A power pack and pushing the amp below 50% volume. The beach will definitely be rockin' when I show up....ha!. Seriously though, in my opinion, having a set up like this makes a portable Bluetooth speaker obsolete. This is like having your home stereo with you anywhere you go, EXTREMELY loud with clear quality sound. I don't normally write reviews, but after seeing the other lack luster and not so good reviews, I had to chime in. I am thoroughly impressed and will highly recommend this Nobsound to anyone looking to power an extra set of speakers. I will definitely purchase another whenever this one goes out.

Great quality, look, sound and super easy it was to set up. It comes with all the cords needed to hook up to an Aux or USB and ofcourse Bluetooth which was super easy to connect. I was up and running in 10 min after opening te box. I bought this for my workshop in the garage to replace a vintage Fisher Stereo Receiver that went bad.No its not audiophile sound but with a few adjustments of the EQ on my music app and decent bookshelf speakers, my shop has music again. it sounds great and gets the job done and at this price, I plan to pick up a couple more for my desktop and my bedroom tv. Great deal!

Nobsound Mini Bluetooth 5.0 Power AmpGreat value and performs pretty darn well. It seems to give a nice neutral sound profile, which is what I was looking for in attaching my monitor speakers.Every now and then it seems to drop its connection, as others have pointed out. You have to unplug/replug the USB and/or the power to get it. to reconnect. Flipping the on/off switch won't do it - in fact, not entirely sure what, if anything, that switch does!Also, the 'PC Mode' announcement is makes when you connect to your laptop is a bit annoying and unnecessary, as others have pointed out.