Class A power amplifier (2):

The voltage amplifier and current amplifier are housed on separate printed-circuit boards. The current-amplifier board is fitted just above the heat sink as shown, while the drivers, current control transistor and output transistors are screwed underneath (or beside) the board on to the heat sink. The terminals of the transistors are bent upwards at 90° about 3 mm from their housing and then soldered directly to the board. All other components are fitted at the track side of the board a few millimetres above the surface.