This simple low power triplicator was found in 90’s American documentation. The diodes can be general purpose types and the frequency is determined by the RC network of the 555.
The amplifier shown in the figure was obtained from the Anlog Devices linear integrated circuits...
If the reader still uses silk screen printing tables this is an interesting circuit found in a 1994...
This circuit monitors the output of a stereo amplifier, checking the balance and balance between...