Test is okay, but I made the same mistake that I had made in nanoDrum: silkscreen of BC547 is wrong. Must be welded reversed (EBC -> CBE).
Anyway now I put the model in the store. Removed the PCB that I used for test and those bought in pre-sale I do not have many in stock … you’d better hurry.
I have not tested the card Teensy (because I do not have)!