old Tivoli model one noise issue

Hello everyone😀

I just got here via googling. I hope it's appropriate to post this here.

I got an old Tivoli model one radio from someone, which has the serial number ending with 0904, so i guess it's been made more than 10 years before.

It actually works fine, there is no hum noise while turning the knob, light indicators, and the sound is also just fine.

The problem is that, there is some kind of noise continuously, while the power is turned on, even though the volume is off down to the minimum level. And that noise, came also out while the volume is on.

And it sounds like the volume of the noise is slightly increasing as well, when I turn up the volume.

Here is the link of the sound clip i recorded with my phone in front of the radio.

Radio Noise by ChoiHaram | Choi Haram | Free Listening on SoundCloud

I volumed this sound clip a little bit up, so it might not so loud as the clip, but still enough to annoying.

and, here are my question.
1. Is there any specific name of this kind of noise?
2. Could I get some help/opinion about the way to fix it?

Thank you for reading