Gary,
I guess if the R-390/A is to be put on a pedestal, never to be plugged in, a complete restoration; then it might matter. Doubt of many of these great receivers are in the back of a deuce and a half, towing a generator, over hill and dale where the ballast tube would make a difference.
For many of us who use one daily, pull the ballast toob, replace the PTO & BFO toobs with 12BA6's, and jumper pins 2&7 of the ballast toob socket. Save $30 to $40 on a toob that doesn't last very long.
But yes, I've heard that the TJ311M01 could be a replacement.
73's
wd8kdg
Craig
Agree 100%. The best solution by far.
The 3TF7 has no value added when using normal residential power.