I'm hearing a tinnitus for over 10 years now, so I know what it's like. :)
That's the most perfect typo I've seen in a while.
I found the frequency of my tinnitus (67hz) and changed the octave until I found the best result (268hz).
When you play two square waves that are slightly off, you also hear a really obvious pulse that corresponds to how off they are (1 pulse per second means they're off by exactly 1 hz, and so on.) I don't know what the experience of tinnitus would be, but assuming you can hear the tinnitus and a square wave at a close pitch, it should be fairly easy to isolate the exact frequency with a binary search.
I found a frequency that was pretty close to what I hear (it's convenient that my left ear is mostly normal), and cranked it in my right ear. I now hear something like a distant swarm of bees, or a server room full of very loud fans.