The project Supply contains a couple of sub-projects which serve slightly different purposes:
Supply – This module is meant to provide symmetric supply for analog circuits. It turns symmetric unregulated voltage into fixed regulated +/- supply. E.g. +/- 18 V → +/- 15 V .
SupplyZwei – This module also provides a symmetric supply. But it contents itself with a single (but larger) voltage. A power amplifier is used to ‘invent’ an intermediate voltage level.
SupplyDrei – This module represents yet another way to supply analog circuits. It quadruples and rectifies an unregulated AC voltage with a Delon circuit. Subsequently, two regulators provide a reasonably stable symmetric +/- supply.