I have had my U2 Pro since january 2023, plugged in constantly since then, powered with a 5V/1A USB brick using the provided cable. Before pluging it in for the first time, I opened it, soldering was good, I just added some solder on a few THT components where I tought it was lacking and cleaned excess flux. The HDMI/I2S port was soldered slightly cerocked, but there were no bridged connections. For the price, very acceptable.
Previously going from my PCs USB straight to my DAC I had a problem on my tube amp hearing all the noise from my PC (GPU activity, mouse movements,...) in my headphones. With the U2 Pro in between my PC and my DAC, everything is compleatly quiet. So I can't comment on the sound change as my goal was to get rid of the noise. U2 Pro is connected with a COAX cable to my DAC, which for me is not a problem since I never had a need or own files above 24/192. All sampling rates from 16/44.1 to 24/192 and DSD work with no issues on my unit.
After 6 months I decided to upgrade the oscillators to Crystek CCHD-957 as I was curious if I could hear a difference. I bought the oscillators from Mouser and soldered them myself using some Mundorf Silver-Gold solder I had on hand. Picture of before and after is below.
@rene555 and anyone else, for reference, my oscilators are for sure genuine, comming from Mouser. I again can't comment on the sound diference as right at this time I started using some higher end headphones (2k - 3k range).
All I know is, I have a clean source for my DAC, if there is a sound improvement great, if not, I stil solved my noise issue, which is mainly why I bought this unit for.