Yeah, those sweep tubes were pretty sensitive; but they weren't as expensive as
some of the other power tubes. I had a Hallicrafters SR-400A which used a pair
of 6dk6's as the final amp. It upt out I think 300 Watts and 450 PEP. The
first time those tubes failed, I was shocked when I took them out to see that
the envelop had caved in on one side due to the excessive heat. After that, I
put on miffin fan on the top of the final cage to keep them cool!
Steve
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