On Tue, May 21, 2024 at 05:54 PM, W7WRX wrote:
<The tube He sells clearly a white base tube.? Check this link.? He had them change specs on these and had to purchase hundreds of them to test before they finally got a good batch.? These exceed Eimac spec now.
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## Tom? dumped the tubes from factory #2? ? (with it's 70+ % failure rate and brown base) and went to factory #1? (with it's 13% failure rate...and the white base).
##? Test any chinese 3-500Z? with a hi-pot tester.? You won't measure? 5 kv? between grid and cathode....like you see on any Eimac 3-500Z.? ? The best you will measure is 1 kv, if that....and sometimes as low as 600-700v.?
##? You won't measure 16-18KV,? from anode to grid, like on any Eimac 3-500Z.?
##? The measured C? between grid and cathode on the chinese 3-500Z's is far more than an eimac.? ?The chinese tubes have the grid spaced closer to the cathode vs? Eimac.? ?The MU on the chinese tubes is 200.? The MU on the eimac 3-500Z is just 130.?
##Per JI, the chinese tubes need at least 5 vac bare min, on the socket, to function correctly....and 5.2 vac, to meet? IMD specs.
The chinese? 3-500Z's? will work fine.... as long as they have the white base...and are matched correctly, if a 2 x tube amp used.? On eimac 3-500Z's.... grab any random pair of new eimac 3-500Z's.... and they are matched up.... since they were? built to exact specs.??
