http://mzentert.ipower.com/studio_works … chive.html

Original 1979 version…
with Distortion instead of Square Wave slider…
It is different than later versions…. extremely rare… way more expensive…
need this schematic for repairing input on mine…

https://www.americanradiohistory.com/UK … 968-01.pdf ^
Practical Electronics Magazine Archive
Practical Electronics began publication in the UK in December,1964 and was aimed at the experimenter and construction enthusiast.
In November, 1992 Practical Electronics merged with Everyday Electronics to become
Everyday Practical Electronics

https://www.americanradiohistory.com/Pr … ronics.htm

Radio Electronics Magazine Archives
Radio-Electronics was an American electronics magazine that was published under various titles from 1929 to 2003. Hugo Gernsback, sometimes called The Father of Science Fiction, started it as Radio-Craft in July 1929. The title was changed to Radio-Electronics in October 1948 and again to Electronics Now in July 1992. In January 2000 it was merged with Gernsback’s Popular Electronics to become Poptronics. Gernsback Publications ceased operations in December 2002 and the January 2003 issue was the last. Over the years, Radio-Electronics featured audio, radio, television and computer technology. The most notable articles were the TV Typewriter (September 1973)[1] and the Mark-8 computer (July 1974). These two issues are considered milestones in the home computer revolution.

https://archive.org/details/radioelectronicsmagazine

https://www.americanradiohistory.com/Ra … r_Page.htm