Back to the project. I will be going with the 3 volt supply. My earbud is rated at 1ma. This amp look good.
The input is 500uv for 1 ma output.
The battery drain is a little less than 1 ma. R6 could be adjusted to vary the Q current. If R6 was 1 meg it would probably be good but for I'll go with 100k and expect to need a volume control.
Time to clean off the bench and gather parts for a build.