08-28-2013, 07:28 PM
It *was* a running design change, and it is documented.
The first 40-150, 155, 180, etc. sets used a 7J7 tube. Then Philco switched to 6J8G. Then they switched back to 7J7.
Don't know why. Maybe they ran into a shortage of 7J7 tubes and used 6J8Gs until they could get 7J7 tubes again?
The first 40-150, 155, 180, etc. sets used a 7J7 tube. Then Philco switched to 6J8G. Then they switched back to 7J7.
Don't know why. Maybe they ran into a shortage of 7J7 tubes and used 6J8Gs until they could get 7J7 tubes again?
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Ron Ramirez
Ferdinand IN