Originally published as a booklet, The Williamson Amplifier is presented on CD in Adobe Acrobat PDF format. Also included on the disc, Partridge Amplifier Circuits. This manual published c.1937 contains eight amplifier circuits using the Partridge Transformers well known for their high-quality audio applications. This CD is not only a singular resource, but also an important historical document which will give the reader unique insights into the tube designer's problems and compromises. Accompanied by more than 40 detailed illustrations, parts lists, and complete construction details. The Partridge Amplifier Circuits includes schematics, parts lists, and construction notes for each amplifier design from their 1937 catalog of early designs.