When powering up an old Philips radio I'm restoring (Restoration of Philips B6X63A valve radio), I noticed a flash from the original Philips ECC83, and thought oh well that one's buggered, and replaced it with a new 12AX7 from the old chassis I bought.
Then while googling something completely different, my eye caught the phrase "heater flash". I'd never heard of it, but I now see it's a "thing", and nothing really to worry about - the general opinion is that it doesn't affect valve life or sound.
An example: https://www.youtube.com/watch?v=W1rwdnxOy7w
Then while googling something completely different, my eye caught the phrase "heater flash". I'd never heard of it, but I now see it's a "thing", and nothing really to worry about - the general opinion is that it doesn't affect valve life or sound.
An example: https://www.youtube.com/watch?v=W1rwdnxOy7w
