± 60 Volt Switching Power Supply for PA

The main part of any amplifier is the power supply. It is clear that to obtain a high output 12-volt battery is not enough. Therefore, we must first create a voltage converter, which enables a bipolar supply +-60V with a capacity of no less than 400W. Digging on the forum found a fairly simple and relatively good scheme.

The brain of this converter is a chip TL494NC, it creates pulses of a given frequency. Frequency set elements R1 and C8. Then these pulses hit the transistors VT1, VT2, which are the control keys for the output transistors. Alternately opening, the output transistors in the primary winding creates an alternating current of high frequency. The transformer increases the voltage to 60V specified, then the current is rectified by a diode bridge. Inductors and capacitors smooth the ripple and high frequency interference. The transformer is wound on a ferrite ring glued two rings size 45 * 28 * 8 marks NM2000. All faces of the ring rounding a file, then wrapped a rag trance tape.

The primary winding is wound around cores 10 0.8 mm in diameter and contains a 2 * 5 turns. The coils are evenly distributed around the ring. On the findings of all the wires are twisted. After the primary layer of duct tape again. The secondary winding is wound around three strands in the same wire and contains 2 x 19 turns.

Heatsink for the output transistors is a duralumin plate, thick 3-4 mm, length about 10 cm and a height of about 3 cm.

To supply the filter unit to bipolar supply +-15V. It is realized by means of the voltage regulator transistors assembled on VT8, VT9 and Krenke 7815, 7915. Transistors and Krenke also have small aluminum plate radiators. To power protection unit made of withdrawal of positive leverage power amplifier. The voltage drop across resistor realizes  R17.

Switched inverter as the amplifier with the terminals of REM, giving her 12 on the radio in, for example, or the ignition switch. When off, the amplifier current consumption is very low. The board also provides a connector for the cooling fans.