I want to design a power supply for 8 IN-14 nixie tubes. The tubes are controlled by a raspberry pi which needs a 5V supply voltage. I found this nixie power supply kit which converts 9V to about 180V. So my current setup consists of a 9V AC adapter, an L78S05C linear regulator, and the nixie supply kit. With my advanced temperature sensing method (using my finger), I have found that the L78S05C is getting really hot and other parts of the supply (MOSFET and Inductor) get moderately hot. I am not sure if the temperature of the nixie supply is a problem or not.
I think the linear regulator should be replaced by a buck converter. Is this the right way to go about it? Or should I try to start from 5V and convert that to the required 180V? And how would I go about that? A flyback converter or two boost converters in series?