OK, somehow I got things backward in my head. I have an old artical on converting 7591 to 5881, and it calls for a 390 ohm resistor on each cathode. Oh well, I corrected it.All I have on hand is a 20 ohm resistor, so I tried it. here's the results:
Plate = 400
Screen = 270
Grid = -23
Cathode = 1.1
I can get a pair of 50 ohms the first of the week. I'm leaving for a music festival tomorrow and won't be back till Sunday evening.
Thanks for the patience.
Dave