This circuit, suggested by an old technical publication, generates white noises from a triode tube that can be a 6C4, half a 12AX7 or 12AU7.
The critical component, besides the tube, is the transformer. In this application the use of self-transformer is not recommended as the insulation should be maintained.
The diode can be 1N4007 and the capacitors are ceramic or polyester. For the source electrolytic the working voltage must be at least 450 V.
In figure 1 the complete diagram of the generator whose adjustment of the point of operation is done in a wire potentiometer.
Figure 1 - Complete diagram of the noise generator.
