"In 1973, instructions on how to build an A48 were hand written and drawn on a sheet of acetate so it could be copied by a Dyeline machine, it was after all before office photocopiers were common place. These instructions gave an assembler step by step guidance on how to construct the amplifier. Each Sugden amplifier is still manufactured by a single person and we have detailed construction files on every product we have ever made." - Sugden Audio