I am using an iPod touch 1st gen 32gb with the go dap, it is loaded with 400 bit cbr AAC files. And I have to say WOW this combo sounds killer with my sony xba-3.
In case your wondering what I put in the holster of the go dap in the last photo, I added electrical tap to the edges for better grip, also I added some foam sticky pads (made for cupboard doors) to raise the iPod touch 1st gen to the height of an iPhone 3GS
Everyone loves the ipod video's dac, it is a wolfson WM87588G. The iPod touch 1st gen uses a VERY similar dac, WM8758BG, I think the iPod touch 1st gen implements the dac better than the ipod video, it sounds more like my imod than my stock video
I have figured out why the go dap gd 03 is so bass light. It turns out that it isn't load induced roll off, the go dap has a built in high pass filter. I think some monster pro copper iem's would sound perfect on this setup