[EICO] Tube for Eico 723 TX

[Richard Brunner]

Re:
"Anybody ever use any of the Chinese tubes?"

Yes.  I have a Chinese type 222 receiver, which is a Chinese copy of the 
AR-88 with improvements, which uses all Chinese mineature tubes. 
Fortunately it came with a complete set of spares, but I have found American 
equivalents for all but one.  Anyway, Chinese tubes are/were made with 
Russian equipment and the early ones were not good, and  were merely graded 
as working or not working.  Later quality improved, and those for the 
military were marked with a vertical diamond with a letter insided.  There 
were three grades, one for generic military applications, a better one, and 
the best for avionic applications.   (I don't remember the letters)  So, 
Chinese tubes of recent manufacture should be fine, and if they have the 
military grading they most certainly are good.

Richard Brunner, AA1P