Red Wine audio offers the iMod – a service that modifies the DAC in 4th, 5th and 5.5th generation iPods. Despite requiring some fine work, the mod isn’t that difficult. [joneeboi] sent in his DIY DAC mod how-to, and even better, it’s suitable for 3rd gen and 1st gen Nanos. The audio signal is tapped directly after the DAC, and the SMD capacitors in the iPod are replaced with high end Black Gate capacitors. This is just the mod feed the best possible signal to your headphone amp