Just in case this helps anyone:
If I lie down in bed with earplugs (I sleep with them, so this is every day) and concentrate on my tinnitus tones in a certain way, I can make them go away for a bit. The "technique" if you want to call it that, is to imagine I've applied a notch filter to the tones, and I'm gradually lowering the gain.
I sleep with ear plugs too and am able to tune out my tinnitus. The more I concentrate on it the more it challenges me so it just becomes a head game between me and my affliction.