This is a bare board of a high-end headphone amplifier. The design is based on Kaneda headphone amplifier. Kaneda is a Japan audio guru who contributes design in Japan audio magazine MJ( stands for Music Journal) for over 30 years. This headphone amp features J-FET differential inverting input and mosfet output. It is a new design by Kaneda published in MJ the last few years work on current mode amplification and represent Kaneda's most update design ideas. The headphone amplifier was found to be highly transparent with exceptional bass performance. Dimension : 104mm x 115mm Thickness : 1.6mm We provide schematic , part list and adjustment procedure to buyers by email after shipment of the item. The assembled board is for reference. This listing is for one piece of bare board. We do air shipping worldwide at US$5.50. We welcome combine shipping.