high pitched noise recording from cassette

I am digitizing old cassette tapes. i have a cassette converter that came with audacity included. i have set the program up according to the directions but as soon as I start monitoring the sound from the usb converter i get a high pitched consistent squeal in the speakers (or earphones) and it comes out on the recording. this sound is not noise from the recording - it is coming from the device or the computer or some interaction between the two.
I am on a mac pro os 10.9.5 and working with audacity 2.0
any advice would be appreciated… have tried workarounds (going thru m-audio, trying to go into a digital camera, using all the different sound devices on computer)

If you want to use the USB connection, try another USB cable. It is quite common for the USB cables that come with “converters” to be faulty.

If you want to use any headphones out or line out that the converter has, disconnect the USB cable. Then connect the appropriate stereo TRS cable from the converter to the line input on the computer (or to an M-Audio interface). Restart Audacity and select the input you are connected to in Device Toolbar.

Note that if you have a modern Mac that only has one audio port for connecting an Apple headset, you must use the USB connection or some other interface like M-Audio.