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Old 7th Jun 2008, 10:28 am   #13
paulsherwin
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Default Re: Another (possibly silly) valve question

Quote:
Originally Posted by Steve_P View Post
Had a thought last night on this, and I'd like to know what others think. ECC85/UCC85 valves often need changing. Could this be why? On many sets, the heater stays up but the HT is switched via the wavechange switch.
If there was any evidence that cathode poisoning would be a problem, it would have been very easy and cheap for the makers to connect the anodes to HT via a large resistor when the radios were switched to AM. They could have referred to the improved valve life in their marketing. The fact that none of them bothered to do this speaks volumes.

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