The work of Prof. Tzounopoulos describing the involvement of the HCN channels and restoration of Kv-channels after noise exposure, along with Prof. Rauschecker's work on a gating mechanism, provide clues as to why tinnitus develops and persists even with little to no hearing loss by audiometric assessment.
For those interested, I have shared the full text research documents for both authors "somewhere" on TinnitusTalk.