I ordered a Fiio E7 last week from Amazon and within two days the volume down button has stopped working. I am returning this amp to Amazon, but now I am questioning whether to buy another E7 or something else. I really like the E7, but I am now concerned with quality issues. Has anyone else had any quality issues with the Fiio products or does this seem an isolated incident? I would be happy with another E7, but would jump to an iBasso D-Zero or possibly even a Digizoid if it was better quality.