We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit (double 555). The relay must be 12 V with contacts that support the horn current.
This circuit was found in an Electronics World magazine from 1990. The circuit can be mounted...
In the figure, from a documentation from the 70s, we have a few-watt amplifier for general use....
This circuit is from 1968 and consists of an amplifier for turntable of the time. The CA3020 was...