Miniosc Audio Oscillator (December 1996):


The pin numbering of U1d is shown reversed -- the inverting input should be pin 13, 
and the non-inverting input should be 12.

Also, the input polarity of A4 is reversed in the block diagram (Fig.1). It should 
match the schematic with the feedback resistor going to the negative input.

Our thanks to reader John Snell for alerting us to this problem.