A Hybrid Tube/MOSFET Headphone Amplifier

A popular hybrid amp design available for headphone use, this single-ended (SE) pure Class-A amplifier is capable of driving headphones between 32 and 600Ω, and was derived from an original tube/MOSFET line amplifier project, published by Erno Borbely in Glass Audio (1/98). Originally published in audioXpress in April 2005, this project was meanwhile extensively discussed in multiple DIY audio forums all over the world and is probably one of the most tested of Erno Borbely's designs, with multiple iterations frequently published on blogs and other publications.