With this circuit you can produce the sound effect passing from one channel to another. The circuit is from Mullard documentation from the 1960s. The transistors may be the BC548.
I found this circuit on a December 1976 Radio Elettronica. The Italian magazine no longer exists, but...
This power supply is not protected from shorts in the output. Output voltage is given by the...
Any power MOSFET that supports the current of the controlled stepper motor can be used on this...