I was just thinking it would probably be appropriate to edit the small paragraph in the second post of this FAQ, under the OTL topology. The description of the OTL topology in the FAQ applies mainly to speakers. Since at least a plurality of tube headphone amps on sale are OTL, I don't think the word "fringe" is appropriate anymore. I think a lot of people read the FAQ and it would seriously mislead them to thinking OTL topologies are bad for headphones. My proposed change is to either make it clear at the top of Post 2 that the topologies apply mainly to speaker amps and not to headphones, or better yet, to append to the OTL paragraph its convenient mating with headphones, which generally have much higher impedance than speakers.