As I said the other day, “It is my estimation that the EL84 would greatly benefit from a lower percentage UL tap transformer.” Whereas there is much to be learned from the current data set taken with the Edcor GXSE10-5K transformer, I have decided that a different configuration needs to be tested as well.
After checking with a couple of different companies I decided to have Musical Power Supplies wind me a custom SE-UL transformer with a 20% UL tap. This transformer will likely not arrive until early June. At that point I can retake the data with the different tap position and see how the results differ.
In the meantime, I will continue to go over the first set of EL84 data to see what else I can glean from the numbers. There is at least one, and maybe two or three, operating points from the 40% tap data which I would recommend using. But I really want to be able to publish both sets of data together and compare and contrast operation.
As always, questions and comments are welcome.