Vermes
Advanced Member level 4
It is an improved construction of amplifier Ws432. Its power amplifier was changed to another, more powerful one. NE116 was applied in this project. New transistors BDW83 and BDW84 with Tda7250 chip were used. After changing some of the elements and improving the paths in print, the amplifier works well. You have to use board designed for the power supply, soft start, because there is a different transformer and control of the fans rotation.
Those transistors heat up significantly at +/- 45V, so you have to assemble a fan for each heat sink and one additionally for the chip. That prevents from the overheating of the systems.
The button once used to change the sensitivity of the VU meter, is now used to switch the amplifier in bridging mode. Bridging is done by inserting a TDA inverting input into the resistor r34 circuit. The amplifier has blue diodes backlight, which looks nice at night. At the very beginning of the operation, the fans start with maximum speed (when soft start is running), and the fan on TDA is still on the constant voltage of 5V.
Link to original thread (useful attachment) – Nowe życie Ws432 + NE116