Turn with me to DTPGB, Chapter 8, Verse 2. Merlin states that the gain to the anode is the same as an ordinary unbypassed gain stage. Then he states that the gain to the cathode is the same as for a cathode follower, and that's where the confusion starts. Since the equations are similar and Ra and Rk are chosen to be equal for the cathodyne, he gives one equation for the gain of either the anode or the cathode. The problem is that the denominator of the cathode gain equation is not the same as the denominator for the anode gain equation, so I don't see how he arrives at Eq 8.1 for both anode and cathode. I pondered this for a while and then realized that there IS a difference between the cathodyne cathode gain and cathode follower gain--the presence of an anode load resistor, Ra. If we take that into account, and add a term for it in the denominator of the cathodyne cathode gain, then Eq. 8.1 makes total sense to me. But that's not how it's presented in the book. Is this an error or am I missing something?