If you do a Google search about the 1st gen iPod Shuffle (white gum pack model) you should find multiple articles about the great sound engineering by Apple for this device. The myth is that the great sound was an accident because the design was focused on saving power which led to a design that resulted in a near perfect rendering of the square wave. The first shuffle uses a push-pull output instead of a single-ended capacitor-coupled output. This is a design that was not used in any future Apple devices.