[TerryG]

Patrick,

Does not the unbypassed resistor on g2 effect plate impedance? If this were the case, then by altering g2 your altering the impedance relationship between the plate and load messing with where these distortion curves land on a plot like the one above for any tube.

If I use a small reostat on the secondary of the output transformer, I should be able to see how the distortion changes with load, B+, bias, and g2 values. Then find the ideal impedance for lowest distortion of any given pentode circuit.

At present the method I found to calculate the output transformer primary impedance seems lacking. Multiply the B+ by itself and divide by the max plate dissipation. So in the 6Y6 above the ideal plate impedance would be 1,656Ω

I can't say why anything would or would not make sense I just perform the experiments, we will know more once I get a test circuit set up and we can all examine the results. You know what they say about theory and practice.

Terry

P.S. BTW, I use a variable regulated supply on g2 so I can change its value on the fly. That is why I can increase the g2 resistor and then increase the voltage back on g2 as well by adjusting the supply voltage.