While working I’ve been listening to music on my Mac on my ER4s. Which is nice, but I don’t like wearing headphones all day. I didn’t want to go out and buy a set of high-end ‘PC speakers’, although something like the Fujitsu TEN might be fun for an afternoon. And anyway, since I bought my B1s, I’ve had a pair of decent speakers spare — either a pair of Neutron 3s, or Dynaudio Contour 1.1s, depending on which I keep as rears on my main system. So I decided to build an amp instead. Looked briefly at a few …