This step of good gain was obtained in an American publication of the 1980s. The circuit can be powered by voltages from 3 to 9 V and the FET can be of almost any type.
This circuit with two 555s was found in the Encyclopedia of Electronic Circuits volume 5 of 1995....
This circuit was found in a 1976 technical publication. It is possible to obtain an 11 dB gain in...
Using transistors at the time, this circuit was found in a 1967 Ferranti documentation. The...