A friend in town handed this to me to check out, presumably on the condition that I write a review about it. Weeks go by - where's that review? OK OK, I'll get to it. First of all, don't listen to me. Check out the plethora of Douk Audio U3 reviews on YouTube: https://www.youtube.com/results?search_query=douk+audio+u3! I think one guy even said it got him to listen to music again! Wow, this $40 amp must be really amazing! A giant killer even! A new standard in HiFi? Crafted by the ancient elves! It's OK. In many ways, the Douk U3 exceeded expectations. It didn't sound flat and boring like that 123 SINAD amps based purely on opamps and the TPA6120 chip under nested feedback loops, with each loop running 125db+ of feedback. The U3's driver/gain stage is opamp, on a DIP so you can roll your own, the output is discrete transistors. The U3 didn't sound too grating either. Maybe a bit glare with extended listening sessions that I bet could be corrected with some warmer or darker sounding opamps. It's a classic solid-state class AB sound. Some grain, a bit of an edge, but not too much. The problem is that most solid-state, even cheap solid state has moved on. Put it this way, the Magni+ is more mellow in the highs. The Douk U3's presentation reminded me of slight headamp version of this, but with just a bit more glare. That's the good news. I have a lot of bad news later. But first, let's measurebate!