8
3.2. Power Supply
Power amplifier is using a 2.3 kVA
toroidal transformer. A soft start is
provided using relays and resistors (on
the front board).
The high anode voltage is made by combining 1x600 V and 3x800V sections (total 3000V) @
1A. Each section has its own rectifier and filter. In the high voltage circuit, safety resistors are
employed to protect the amplifier against overload (rear board).
The source for screen grid is taken from 600V section, regulated by parallel stabilization with
BU941 and delivers a voltage of abt. 480V at 80mA. The -75V for the control grid is
regulated by PWM from uP
.
CAUTION
Primary section of the transformer is switchable for 220 - 240 VAC. Factory setting is 230VAC.
If the AC voltage in your network is 220 or 240 Volts, you need to set the correct value
before first starting of the PA.
See part 7.1. for more information.
3.3. Safety Devices
Control and monitoring circuits ensure control and safety during malfunctions of the PA.
These are on the Control board, which is located on the chassis subpanel.
One of the very important safety
elements is mechanical switch for
transformer primary (AC) blocking at
opened amplifier.
4. INSTALLATION
NOTE
Read this chapter carefully prior you will start installation. Before unpacking inspect shipping
carton first, if it is not damaged. Keep all of packing parts for possible future shipment. Check
unpacked power amplifier. If you find some damaging, contact your dealer immediately to
keep full warranty.
During installation go step by step according to the next parts.
