Crazy HV issue on a Tele-Tone TV149

[Zenith26kc20]

If I remember, the TS-4 is around 140 volts B+ and 280 B++ (doubler circuit).
I can't see how a AC tripler would skyrocket B++ (if it has). Tripling or the existing circuit would already produce the maximum voltage (400?) volts ((wow!)). With tubes instead of seleniums, there is no problem with efficiency differences from silicon to selenium.