[Mike Rivers]

Ben Bradley wrote:

Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson