Like in this picture, marked L1_:
If the previous pictures posted by RuiCanela is your amp, I fear that your oversized resistors and your ferrites are causing problems.
Also, make sure the capacitors' tops and the screw holding down the 7812 is not touching the case. Make sure the screw's head is not cutting into the bottom plane.
Edited by ShinyFalcon - 3/6/11 at 4:48am