[morzh]

Terry


I understand now (after looking at the sch) why the 6H6 does not blow up - the tubes are serialized, not parallelled.

So the resistance of the 6H6 is 20 ohms (6V/0.3A) and 12H6 is 80 Ohm (12V/0.15A), so at more or less the same current the 6H6 tube instead of getting 6V will get 1/4 volts it needs. Well, a bit more as the current is raised a little. Let's sai 1/3, that is 0.1A. So the tube will be working, but really way under the specs. Plus the voltage on the rest of the filaments will be higher which will stress them a bit.


So, I am sure the radio will work that much better with 12H6 in it.