Historic Transistor Construction Project

Germanium Power Transistor Audio MiniAmp



The original 1956 amplifier was developed for a specific purpose, which was to provide portable, battery-powered functionality to a spring-wound phonograph. The updated amplifier, shown above with a portable CD player and a standard CD for size comparison, has been developed with the following set of requirements (and results):

(1) Provide good sound quality and output level. The audio output level is more than sufficient to provide adequate listening volume, similar to, for example, a small set of computer audio speakers. Sound quality is excellent, especially accentuating the treble content of music (vocal and instrumental leads). Bass response is limited, which is not unexpected, considering the small size of the case and internal speaker.

(2) Easily used with modern audio products, including portable CD and MP3 players, personal radios, and computer audio. The output level obtained from the earphone jack of all these types of modern devices is at the correct level to provide input to the MiniAmp. All stereo signals are converted to mono by the amp, and volume can be adjusted using the volume control of the input device (CD player, for example).


Go To Penfield MiniAmp - Page 3



COPYRIGHT 2004 by Jack Ward. All Rights Reserved.