In the original publication of the 90s a 556 consisting of a double 555 is suggested. The circuit drives a speaker with good power. The power transistor shall be fitted with a heat sink.
Figure bellow shows how the 4088 or 4018 can be used as a touch switch. Two metal plates separated by 1 mm...
An interesting interface solution that can be provided in some cases is the one shown in the...
Originally created to feed the filaments of a 12AX7 as an audio preamplifier to eliminate the...