120Hz hum almost has to be something directly connected to the main filter caps, as that is where the AC is removed. Check the AC voltage at the plus and minus rail points on the main caps -- more than a few mV is a problem. Check your ground connection at the main filter caps, and make sure you have exactly duplicated the original wire configuration -- it matters where the wires are soldered on. If the ground wire for other parts of the power supply is attached BETWEEN the center point of the capacitors and the chassis ground point, you can broadcast the ripple on the main filters all through the power supply and amplifiers. Ground for anything other than the filter caps must be attached on the other side of the ground point.
The other source is a very leaky diode in the rectifier -- did you replace the rectifier diodes? If not, I would. Usually a leaky one will give you 60 Hz hum I think, though as the rectified voltage will have a "stagger" with one wave higher voltage than the other. Rectifier diodes are inexpensive, and faster lower noise ones are available.
You should also verify all ground points on the schematic and check any ground connections to the chassis, either wire or screw connection. Screw connections often have solder pads on the board, and if they are worn away or dirty you won't get a good ground. If you have a bad ground somewhere, you can get a "ground loop" where the ground is through some other part of the circuit. A wire broken inside the insulation or a corroded wire wrap can cause a "flying ground" or an indirect ground through some part of the circuit instead of direct.
