The Amplifier Power Supply

Part B - The Transformer Side

The second power supply circuit diagram shows the HT and LT transformers and associated circuitry including the HT capacitor board and the HT Divider / monitor board. 

A couple of bits are different to that shown in G3SEK's control card design:

• The HT divider is different. As I was limited in physical space I used two 10M ohm @ 7.5kv resistors rather than 16 1M ohm resistors!

• The 240v blower is driven from a secondary winding on the HT transformer so that the amplifier could still be used with 120v mains (line) supply.

Click on the component to see a photograph

The Power Supply, transformer Side

The key parts of the above circuit are:

• The HT and LT transformers

• The 8877 cooling blower

• The HT bridge rectifier and capacitor bank

• The HT monitoring board

• The R104 HT surge current limiting resistor

Parts List