For the electronics enthusiast a tube audio amplifier makes for an interesting ... It follows a so-called ultra-linear circuit, with a tap on the output transformer feeding one of the pentode ...

There’s a mystique among both audiophiles and musicians about vacuum technology, thus having a tube amp still carries a ... it’s not for audiophiles. The circuit is a pretty conventional ...

There are a couple of reasons I suspect it's taken this long to see a vacuum tube in a pair of headphones. Tubes are hungry ...