Little Dot I+ Tube 6JI/ 6CQ6/ WE408A Hybrid Tube Headphone AmplifierLittle Dot I+ 6JI X2 Tube standard The Little Dot I+ is a hybrid transistor vacuum tube headphone amplifier, which combines the smooth, musical sound of tubes with the high output current of transistors. The vacuum tube stage is run in Class A, the MC33078 operational amplifier (socketed) provides voltage amplification, and BD139 BD140 transistors serve as output buffers. Little Dot I+ 6CQ6 X2 Tube Upgrade The Little Dot I+ is specifically designed