The original project describes the bass-boost control in the feedback loop:Not that simple for me audioguru =) The feedback network looks relatively complicated, at least to me.
NO - they are power supply decouplers.my work colleagues said exacally the same! the transisters are the push pull part of the circuit and the op amp amplifies the circuit! they couldnt explain the feedback tho! they also said that C3 and C4 were references for the opamp! would you agree?