Some digital modules require a 5V supply in addition to the /- 12V. While recent cases, bus-boards, or power systems (such as TipTop Audio, Zeus line, or MakeNoise Mini-PWR) provide this 5V source, older Doepfer cases are only equipped with 12V and -12V.
To bring to your system the 5V rail, an adapter such as Volts can be used.
