How to filter hum from transformer for audio rectifier
The toroidal type mains transformers do not have a lot of magnetic leakage. 

The hum you hear is more likely at 100Hz. 

The hum that remains with no input connected can be reduced by increasing the filter capacitor but adding a proper voltage regulator (linear or switched mode) would help more. 

The hum when CD player connected is probably due to differential ground noise from the two separate mains supply points, sometimes if you can use a common power-supply ground you can reduce it sometimes this is NOT possible (such as when analogue and power grounds are not tied together in the devices).