I want to record live music directly from my sound board on my Samsung Galaxy. I assume this would be done by connecting the 3.5mm microphone jack on my sound board to the Galaxy's USB port. There are plenty of products that work on Windows, but what about Android?
I assume the USB connection isn't the main point? You could look into a TRRS splitter to fit your 3,5mm plug into the headset jack on your phone. Here's one example, just to give you an idea of what I mean.
This way you can use a normal recording app to capture analog audio from your soundboard. Just be careful to check the levels since the jack isn't a line in jack, but a mic in jack.