6Ж4 (6ZH4=6AC7) pentode made by Svetlana 1979
<a href="//commons.wikimedia.org/w/index.php?title=User:Retired_electrician&amp;action=edit&amp;redlink=1" class="new" title="User:Retired electrician (page does not exist)">Retired electrician</a>
2023-01-02 00:28:37
<span class="int-own-work" lang="en">Own work</span>