John, I forgot: Your diagram shows a TPTG oscillator. The pop sci article is also a TPTG oscillator. Are most tube TC diagrams of this basic configuration? Why? Also, with B+ running around all over the place via ground, a fil xformer with center- tapped sec might do better at keeping RFout of the filament leads. Use 0.01 caps in each lead to a grounded center-tap. ZEKE