Historic Transistor Construction Project

Germanium Power Transistor Audio MiniAmp  



This top photo is a stylized version of the front cover of the August 1956 issue of Radio and Television News, which features a Transistorized Phonograph construction project, designed by Paul Penfield Jr.  The photo below shows a recently constructed germanium power transistor audio amplifier that uses components and design similar to the original developed by Paul in 1956.  This TransistorMuseum™ Historic Construction Article provides all the detail you’ll need to build your own MiniAmp. 



Modern Version of a

 Transistor Audio Amplifier

 Based on a Classic 1956 Design

By Paul Penfield Jr 



The transistor was invented at Bell Labs in 1947, and for the next decade or so there were a number of interesting and unique construction projects highlighting this new technology published in electronics hobbyist  magazines of the day.  These early articles were the first to explore and popularize transistor technology for use in such applications as portable radios and audio amplifiers.  Paul Penfield Jr (use this link for a detailed Oral History) authored  many of these transistor construction project articles, often presenting unique or first time usage circuits.  The MiniAmp described in this current project is an updated version of a germanium power transistor audio amplifier, based on the circuitry developed by Paul for a portable transistorized beach phonograph, and published in the August 1956 issue of Radio and Television Electronics.   This updated version performs surprisingly well and has multiple uses with current technology, including portable CD and MP3 players, personal radios, and computer audio.


Go To Penfield MiniAmp - Page 2



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