Humm from phono but not dc or aux ?

No, you need to check the ground on your turntable and tonearm. Some cartridges are prone to humming. Grado has a history of this. If you crank the volume all the way up there will always be at least a faint noise on the phone input because of the high gain. With less expensive equipment it can be quite noticeable. 

You have to figure out what is causing the problem before you start spending money. Is the hum in both channels. Are your phono cables shielded? What happens when you move the ground wire? 

@atmasphere , Not just Regas. I personally saw (heard) an early Reference do it on a Sota with a grounded motor. When you moved the tonearm closer to the ,motor it got louder.