We found this circuit for musical instruments in the March 1992 Radio Electronics magazine. The circuit has outputs according to the desired scale from a crystal oscillator at the indicated frequency.
We found this circuit in a documentation from 1966. The transformer is output for transistors. Resistors...
This simple guitar distortion effect was found in a documentation from the 90's. The circuit is...
Using a sensitive crystal or ceramic microphone, this circuit can pick up faint sounds through a wall....