Wayne Colburn of PASS Labs was kind enough to release a new DIY headphone amp circuit into the wild, the WHAMMY, standing for Wayne' Headphone Amplifier Must Make Yourself. It's a nice simple build, no need to match parts or make adjustments, so it's perfect for the budding DIY builder. It's also inexpensive. The PCB, parts and chassis should be under $200 without much effort. Jim Tiemann aka 6L6 of DIYAudio has been kind enough to coordinate the project and has been instrumental in making it accessible. You can read more about the project here: http://www.diyaudio.com/forums/pass-labs/317803-whammy-pass-diy-headphone-amp-guide.html Boards can be procured here: https://diyaudiostore.com/collections/printed-circuit-boards/products/whammy And you can learn more about the circuit design here: I'll be building one myself and hope some of the members here will as well.