MoKen

I've had it for years in both ears. You get used to it. Unfortunately, it will mask the pitches that match your buzzing/ringing, so you have to recognize that. I recently had a nurse tell me that ibuprofen and similar drugs make it worse - something to do with thinning the blood. Just a rumor. I've tried to notice whether that makes any difference for me but usually forget. Definitely find a system of ear protection that works for you. It's been a long quest for me. Now I mostly avoid loud musicians...

I use the bass version of this with my Gold Tone Microbass. Roland Micro Cube I'm very happy with it and it seems to tick most of your boxes. I know Roland is not well regarded for keyboard amplification but seems to be good at this job.

CL cry for help https://chico.craigslist.org/muc/d/orland-yamaha-moxf8-please-help/7063600346.html

http://www.sweetwater.com/store/detail/Ventilator