Ondolina 412 AC

• Internally, the radio is divided into 2 sections: the radio in the bottom half and the power supply in the top half of the housing.
• In case of the batteries version, the power supply section is left empty to make room for the (storage) batteries. This version has a control voltmeter with a push button on the left side for the filaments.
• The AC mains version has an "Oxymétal"¹ rectifier. There is a rheostat, a push button and a voltmeter on the primary side of the mains transformer to compensate for voltage changes and a current regulator to keep the filament current constant.
• The DC mains 110V version and the DC mains 220V version have an internal resistor block to adjust to the mains voltage and a rheostat with a push button and a voltmeter to compensate for voltage changes; also a current regulator to keep the filament current constant.
• There is a tone control on the backside.
• There is an alternative tubeset from Dario: R81 , R76 , R76 , R77.
• All versions of this radio still need an internal 15V negative grid voltage battery ("C" battery).
• The soffit lamp on the back of the power supply is a current regulator.

¹ "Oxymétal" (copper oxyd) rectifier.

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Elenco delle radio e altri apparecchi della SBR Société Belge Radio-Electrique, Bruxelles