Marantz 10b hum

First thing to do perhaps is to check the tubes. They can cause low level hum. Just solved that problem with one of my amps which had a very low level hum in a tube which served both channels.

I agree.Even with the age of the tuner,its surprising how long
some of the gear from then lasted.I'd check the tubes first also.

I have now replaced every tube with a NOS tube and the hum persists. I then replaced the three 10uf and one 20uf electrolytic capacitors in the power supply. Still hums, but the sensitivity is excellent. Any other ideas? Thank you for any asistance you can offer.

Have you tried reversing the 10b's a/c plug orientation in the wall?

And to clarify: Do you hear the hum from the Marantz itself or the speakers?

Thank you for your response. The hum is heard through the speakers. It sounds like a 60 cycle hum.I will try reversing the power plug. I suppose it is not polarized.