Voltage Boosters

Voltage boosters, or voltage multipliers, are used in many effects containing tubes. There are a few ways to go from a lower voltage to a higher and you can do it with both AC and DC. But to multiply a DC voltage you essentially make it into AC by pulsing it.

AC voltage multiplier

This is a voltage multiplier that uses only diodes and capacitors. The shown configuration multiplies the incoming voltage by four (minus four times the forward voltage of the diodes).

Voltage multiplier AC using only diodes and capacitors.

A voltage booster. This is essentially the same as the one posted above, but using a 555 timer to generate a square wave instead of using AC.
More voltage multipliers
Voltage multiplication by transformer - Using a transformer to go from 6Vac to ~110 Vac to about 150Vdc.