Now I'd truly love that computer as a talking point in say the rumpus room of my house, I could entertain my techie friends for hours. And it would take on extr

Now I'd truly love that computer as a talking point in say the rumpus room of my house, I could entertain my techie friends for hours. And it would take on extra importance in winter in keeping my house warm. I've not used 6N3P tubes before but looking at the circuit it seems to me a 12AT7 (an old favorite of mine) would substitute in that circuit almost without alteration. Then again with a tweak or two either the higher gain 12AX7 or its lower gain cousin the 12AU7 would do.