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To the hardworking and or lucky owners of VF14 U47's (nuvistor and otherwise modded 47's need not read further), a reminder to check the B+ voltage regularly. Now, if your first question is "what's B+?", PLEASE have someone else, who is qualified with high voltages, to do this for you.
As real, original U47 power supplies age, the B+ often creeps up, resulting in a U47 that "sounds better than ever", but, reduces the life of the already elderly VF14. I have seen as high as 130v (supposed to be 105v) before the tube finally gave out. If you have an original psu you will likely be affected by this. There are various repairs to counteract this climb, ultimately leading to replacement of the power transformer or the entire psu.
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