Does this mean they are the same?
“Check the specifications below carefully if you fit a PSU not supplied by Elektron ESI.
The PSU should be stabilised, deliver a voltage of 6V up to 7V DC and be able to supply at least 400mA to power the SidStation. The connector has a diameter of 2.1 mm. The connector should have the positive voltage on the inner core, and ground on the outer ring. Please check that this applies to your PSU before powering up the SidStation as both this standard and the opposite exists.”