Hy-Hy!!!,
I think it is time to measure tha amp again. It has gotten a bit on the heavy side...but that may have improved its power delivery.The E-Linear plate-to-grid NFB will do a bit to level the response. The 20-20 lineage of the output TX should grant it full power down to its advertised low frequency limit...:)
I will measure it soon. Must get proper load that won't overheat.
cheers,
Douglas