Role of diodes and one resistor in this schematic:

[rockgardenlove]

http://www.tricountyi.net/~randerse/amp.htm

On the last power stage of that amp, what is the purpose of the two diodes and that 390k resistor?

Thanks!

[Sir H C]

Two diodes are biasing the output transistors the 390k is biasing the transistor that drives the power transistors and gives a bit of negative feedback to the stage.