This vacuum tube amplifier project was inspired by the Spare Time Gizmo's 6T9 tube amp (see Mark's 6T9 Tube Amp and Ultra-Linear 6T9 Tube Amp). This got the ball rolling of ideas in my head and soon it was evolving from one idea to another. I decided to make the amplifier with a push-pull output stage using circuit ideas from my EICO HF-81 and my RCA Receiving tube manual.