I'm kinda on the fence here, should I try the edi solid-tube r-3ds3 in the set, or stay with the 3A3C that's working in it now?
The r-3ds3 was not really made for this set, but should work (guess) as 1 of the 3 cathode pins does match up, pin 2 the others go nowhere, 6,8.
https://www.datasheets360.com/pdf/8329566707472946635
This is the only info I can find, not exactly for the edi, but I'm sure all r-3ds3 tubes are the same.
So, on one hand, the 3A3C is working OK, but on the other, using the r-3ds3 will lower the load on the FBT/HOT cathode. Choices, choices...