An article in Radio Electronics magazine from November 1958 showed the construction of this tube audio oscillator. Note the use of lamps as a stabilizer to obtain better sinusoidal signals.
I found this circuit in a 1980 documentation, but it can be easily assembled with BC548...
Originally this circuit was designed to operate with microcomputers from 1988, but it can be...
This circuit was found in an article about the 555 in the November 1992 Radio Electronics...