Some old "hi-fi" schems

[Nasse]

Landed safely from boat trip from Helsinki to Tallinn and back. Some heavy rainfall at Tallinn, so the sightseeing walk at old town was short.

Okay I promised to post few cmos inverter circuits (from an old paper that I archived too well so I was afraid I have lost it, but found it)

The another is a hi-fi (don´t look the distortion figures too carefully...) preamplifier with tone control. I never built it, which i regret

The other is simple matrix for generating sum and difference of two audio signals (A, B). I built it with exact component values and 4001 chip some 25 years ago, and it worked just nice. I used it for some well-known four-channel trick that hobbyist have experimenting since birth of stereo. For that we now have dozens of better circuits done with opamps and digital stuff. But maybe it is useful for some hobbyist, don´t know

http://img.photobucket.com/albums/v411/Nasse/tcntrl.jpg
http://img.photobucket.com/albums/v411/Nasse/sumdif.jpg

[gez]

Thanks Nasse, much appreciated!