Switch B&K ST2140 and B&K pre-amp Ref 5 S2 from 110V to 220V?

Dear all,


I 'm looking to buy an US imported B&K ST2140 and a pre-amp REF 5 S2 here in France where power is 220V. Both manual mention a possible switchable voltage back and force from US 110V to EU 220V. Anyone knows how it works exactly? There seems to have no buttons for that on both chassis.


Thanks.