Everything ok, waiting to play more than 100hours to see effect.
I am an experienced personnel in this area and didn't find any difficulty for assembling. However ,because this is a circuit board type ( can't see the detail connection ) , people , in general , needs precise assembling explanation . One serious point is the NFB line. Probably you changed board arrangement ( L &R ) , my board arrangement is upside down to the picture you sent. So at first arrangement ,I found it is Positive Feedback(Not NFB). I immediately understood it is PFB and modified the NFB line to the board ( P1 and P2) and is OK. I don't know if beginners can solve this mistake. Another example of issue is earth line. This is also a sort of trial & error. Clear picture of the line to GND is essential and standard level of residual noise is helpful. But in general I am quite satisfied.