User Manual

7
Top view on the opened OM2500 HF
Tetrode GU84B PWR meter Blower Switch-on board
Output Pi-L Circuit Tuning capacitor Power supply board
Subpanel
3.2. Power Supply
Power supply of the amplifier is comprised of two of 2,0 kVA toroidal transformers. A soft
start is provided using relays and resistors.
The high anode voltage is made by combining 8 x 350 V (total 2800V) @ 2A. Each has its
own rectifier and filter. In the high voltage circuit, safety resistors are employed to protect the
amplifier against overload.
The source for screen grid is regulated by parallel stabilization with BU508 transistors and
delivers a voltage of 360V at 100mA.
The -120V for the control grid is regulated with zener diodes.