SMSL A100 Amplifier Hifi, Stereo Amplifier Uses Infineon's Power Amplifier chip MA12070, 2 * 80W Output Power, USB Multi-Device Support, Bluetooth 5.0 with Circuit Protection

The product in general is serving me very well - driving 2 KEF Q150's and the sound quality is excellent through a DAC or via USB with windows. The sound quality with the onboard DAC on the A100 is very clear.The biggest gripe I have is that it ONLY supports A2DP - so 345kb/s at 48 khz. For most people this will be a bottleneck for sound quality. I notice a significant lack of clarity in comparison. Given that the product page vaugely says "Bluetooth 5.0" - I can't really fault them for false advertising, but it's annoying.If your main plan is to use this for bluetooth - avoid. If that's just a nice to have that you won't daily drive - then this machine works very well for the price.

Bought as a low-budget replacement for a significantly more expensive amp (NAD D3020) which died, and I've got it powering a pair of Dali Zensor 3 speakers connected to my PC.It does the job nicely. My aging mid-40s ears aren't very good at comparing hi-fi gear any more, but I'm happy with the sound quality. And the amp remains cool if left powered on for fairly long periods.The only issue I had was that when connected by USB to a Win10 PC, there was a long delay in Windows shutting down, when went away if I disconnected it. There didn't seem to be any driver updates available to resolve that, so I'm using the analog audio input instead.Haven't used the Bluetooth functionality yet, so can't comment on that.

As an amp these seems good, but the USB connection does not work with a Mac so if that's your use case definitely don't buy this.Running through the analogue input this did a good job with a pair of Q Acoustic 3020i speakers and a 3060s subwoofer.However, when connected via USB to my MacBook things got worse. When it was working it sounds good but the connect would random drop in and out. Worse, if you launched Zoom or Microsoft Teams sound would stop and the Mac would hang for thirty seconds until the amp disappeared from the list of available audio outputs. Looking in the Console logs you can see many errors for the sound and USB daemons. It seems the USB audio standard has not been implemented correctly for the amp. This is not a surprise given that is uses a USB A to USB A cable which is itself non-standard.

Overall, it's excellent quality for the price. I've paired it with Elac B5.2s speakers and there is no distortion.I did mainly want to use Bluetooth with it, but it's not good. It often breaks off when my phone is literally a metre away (Samsung S21+). Generally it's okay and quality is okay but nothing great.EDIT: Bluetooth sound via my 2017 iPad Pro 10.5" is perfect. There is some connection fault to my S21+, which is perfect with the Galaxy Buds. So it's not this amp that is at fault. Not sure what is. USB is still the best.Then I tried it with USB. Sound quality is completely different. Every note is clear and it's allowed me to hear notes that I didn't know were there. The bass goes considerably lower on USB connection. The Bluetooth connection made me think I'd need a subwoofer but I don't.Just use the USB connection with this and it'll perform just as well as any other amp that costs 3 or 4 times more.