I created this case to hold the famous ODAC external DAC board and DIY O2 headphone amp, designed by nwavguy. O2 Amplifier: http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html ODAC D/A Converter: http://nwavguy.blogspot.com/2012/04/odac-released.html The two unique features to my design are 1) Wall power socket relocated to rear and 2) ODAC placed on bottom of O2, retaining the two 9V battery slots. EDIT: New version (v2) has improved fit and supports standard power jack configuration, where the socket is on the front left! This can be used for the O2 amp, alone, if you choose not to add the ODAC or you want to add it later. You will just be left with an hole in the back for the ODAC USB port.I printed in ABS with 2 shells, 10% infill, and supports (for front holes). Download both files and print, both, top and bottom. I print with top and bottom down on the print bed for a nice smooth finish. Download the original files for the rear jack mod, or v2 files for the standard configuration. Make sure to let me know how it goes!