The other good news is that these tubes are not even slightly microphonic, as is often the case with submini pentodes. The heater requirement is 6.3 volts / 150ma. They glow a real nice orange too. So I'm planning to revamp a number of my old designs using these little tube, and maybe do some new designs too, basically for the common good of all mankind. I cut my teeth on this little boost, just to check the tubes out really. To power the heater I just put two tubes on the breadboard and ran the heaters together in series from a 12 volt supply. Probably the easiest way to power the heater in a pedal would be 7806 voltage regulator. More 5840 designs to come...........
5840 data sheet: http://frank.pocnet.net/sheets/127/5/5840.pdf
