There have been a few requests for tube based pedals and this is one I did previously. Based around JuanSolo’s 12V Boob Tube which is a Valvecaster variant, but here with a 33 – 40V supply via a charge pump. Make sure you choose appropriate rated capacitors for the voltage. This is verified and apparently sounds great.
Here’s the tagboard layout:
And here’s a charge pump, if you supply it with 12V you should get close to 40V from the 33V output point. The ICL7660S can accept a 12V supply but that’s the maximum for that IC, but you can’t use the MAX1044 at 12V.
If you want to supply the charge pump with 9V and so avoid using a 12V adapter, you could use a 12V regulator off the 17V rail to provide the 12V required for the heater, or maybe even a voltage divider from the 25V rail. In this instance you would only get around 33V for the plates though.
Here’s the pedal built up and looking very nice, built by candletears7:
