[RadioSvit]

Thanks Arran for the very interesting information.

  """"By the way, why does the tube next to the 6V6 need an adapter?""""

It's very simple, I did not find the original radio light bulb 6SF5 and therefore replaced it with 6SQ7, which has very similar characteristics. In order not to violate the original installation, then made the adapter. By the way, if you have mentioned, then the problem of shifting the operating mode of this radio lamp is solved very originally. Not a honeycomb in a cathode, but a 1.5 volt battery in a grid lamp! I met this for the first time in my household radio.