[MrFixr55]

After reading the entire thread, I don't know if a 01A can drive a cone speaker. A 112A or 71A can, but you would have to run separate C- and B+ leads for a 71A, as the B+ was only 45 or 90V for the 01A audio tubes with no bias. A 01A, even at 90V plate voltage is not enough to drive a cone speaker IMHO. Running a 71A or 112 with no bias gets you more power but they sound horrible with no bias.

A-K did not offer a set with an option for a '71A until the AK20 Compact, AK 30 series and 35. The 20C has a single C-lead that biases the 1st Audio and the Audio Output tube. This limits the bias level used. The 30, 32, etc. and the 35 have a single C- lead that biases only the output tube, as one can go to whatever you have for batteries. 180V on a 71A plate with -22V on the C- will get you 0.7W, same as an A-K Model 40 or Radiola 17, 18 or 60.