I have looked into the impedance ratio of an OT before and it's function, and probably forgotten what I learned because I had no practical application of it. Now more recently I have been looking at the AC signal size as it progresses through the amp, it is interesting and I've learned a lot and now want to complete my measurements in the last place, around the OT, and at the same time see if I can verify the impedance ratio, turns ratio, voltage ratio in the theory of audio transformers. I'm going to do the impedance ratios calculations, and measure the signal voltage on both sides of the OT. Where to measure these voltages? On the output side the place to measure the signal voltage is the speaker terminals. On the input side the two choices are to measure the signal voltage at the plate, or accross the OT primary. I will try both ways and see which provides the better results. I just had the best spell check fix: I thought I typed measure and it turned into misjudge.