Miden i did that, and now i don't get sound at all and the little light doesn't lit when i press the keys on the keyboard.
As soon as i select the echo thing under Options > Global, i have sound and the echo is still present.

the echo i get: I press the C key and after i press it several times i also get a sound like i'm pressing the same note 5 octaves downwards.
and if i play several notes some sound, and some don't.

i don't know what to do