persistant buzz from cassette tape recording

I am running Audacity ver 2.2.0 on Windows 10 64bit ver. 1903.

I am trying to record from a cassette tape using a usb tape converter. The converter is working fine. The problem is with the recording itself. There is a consistent buzz throughout the recording. I feel like a notch filter could solve the problem, but I don’t see how to do that using the available effects.

The file I am working on is attached.

Any advice would be appreciated.
anyone can whistle.aup (6.88 KB)

“.aup” files don’t contain any audio.
Need to upload a few seconds of “.wav” file instead,
see …

BTW the offending noise should be visible on spectrogram view as continuous horizontal line(s).