[Ian Iveson]

I often see the term flea watt amp, but do not know what the cut off
point for this is. What is the threshold between flea watts and the
rest?

Wattage? No wonder you are confused.

750 Fleapower = 1 Watt
750 Watts = 1 Horsepower

Anything up to 1W should be measured in Fleapower. Over 1.33 Watts
must be measured in Watts. For powers from 1 to 1.33W, it's optional.

The challenge of flea power is the matching of amp to speakers to
space. I gather this is not just about power requirements and
impedance. I assume there must be many characteristics that must mesh
somehow. If you want to hear the difference when you swap valves, flea
power is the way to go. Less tight and more euphonious, I guess, if
you get it right.

cheers, Ian