In his search for a good sounding headphones amplifier, Rob Scheepens has experimented with, and listened to, several different amplifier topologies. These were all tube based, like Single-Ended, Balanced, Standard Cathode Follower or White Cathode Follower, with the latter proving to be the best sounding of the lot. Eventually, he felt the all-to-familiar urge to refine the design. Having worked with tubes in amplifier designs for years, he decided to consider the use of semiconductors, and try to design around whatever was available in his parts bin. This article is the result of the design process which resulted in good sounding amplifier (at least to Rob's ears) with some interesting features and parts, like a dual gate MOSFET as input stage.
The parts bin headphones amplifier