[MrFixr55]

Congrats Mike!!!

Couple of thoughts. Wonder if that roughly 400Hz hum is feedback? My Radiola 16 has the detector tube on a shock mount A lot of times one sees the Model E speaker sitting right next to or on top of the radio cabinet. Consider puttng the pord or the speaker on foam to see if that helps.

RE the distortion, I wonder of it is being overdriven. Pretty loud for 01As which put out somewhere about 10 mW when used as the output tube. You can try a 112 but I think that it would be helpful to bring out the return in the interstage trans secondary so you can provide the correct bias. I remember trying a 112 at 90V with no bias and it sounded horrible. Somewhere I made a table in a previous thread as to the relative output wattage at various voltage and various bias for 01A, 112 and 71A. At 90V B+ and -4.5V C-, a 112 puts out 30 mW. at 135V and -9V, the 112 puts out 370 mW. However, you want to have a separate B+ for the 2 RF amps. This is not hard to do. Just disconnect the B+ between the board and the island, feed 135V at the Island's Amp B+, move the B+ on the A / B cable to 67.5V, disconnect the secondaries of both audio xformers form ground in the island and bring out a common for them to -9V on the Arbe, connect C+ to B- and you're in. Only other puzzlement is that the RCA receiving Tube Manual calls for a load resistance of 8700 Ohms but these speakers or horns are only about 1K to 2K Ohms. No transformer, RC or LC coupling is specified. On my Radiola 16 the specified output is a 112, the 112 and the 01A 1`st Audio have a B+ of 135V and C- of -(V. The speaker is directly between B+ and the 112 Plate. The RCA 100A speaker is similar in function to your Model E.