TRANSISTOR MUSEUM ™  

Historic Transistor Construction Project

Germanium Power Transistor Audio MiniAmp

  

 

 

THE ORIGINAL AMP

The schematic of the 1956 amp is shown above.  There are four germanium transistors, a technology still new to experimenters at that time.  Of special note is the 2N68, which had just been introduced by Sylvania as a “PNP medium gain, high power transistor for moderate frequency applications”.  What this meant was a maximum of 4 watts output (using the massive metal heatsink for heat dissipation) at a frequency of 400 kc (yes that’s kilocycles).  This was “state-of-the-art” for 1956 germanium power transistor technology.    The three front-end transistors were all from the well known Raytheon CK722 series, and best results could be obtained by “hand selecting” individual transistors.

 

 

Go To Penfield MiniAmp - Page 4

 

 

 

 

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