I suspect those are ferrite beads. They're usually to filter out EMI/EMC rather than clean up the audio, though they can help protect inputs from RF. They usually look rather like this: clip-on ferrite bead, or are heat-shrunk on.


Jazz relative beginner, starting at a much older age than was helpful.
AVL:MXE Linux; Windows 11
BIAB2025 Audiophile, a bunch of other software.
Kawai MP6, Ui24R, Focusrite Saffire Pro40 and Scarletts
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