300B SE stage. Max output power as function of load impedance and idle current. Original Western Electric data
Western Electric Co. // adapted by <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)">user:Retired_electrician</a>
Western Electric 1939 datasheet <a rel="nofollow" class="external free" href="http://www.tubebooks.org/tubedata/we300a_b.pdf">http://www.tubebooks.org/tubedata/we300a_b.pdf</a>