I bet Paul loves these stories… hates those “fire bottles”.
I just had a Mullard NOS CV4003 / 12AU7 in my PrimaLuna HP integrated go noisy… sounds like static…fitzz… goes quiet … kinda random. Upscale Audio said the 6 month old tube was out of 90 day warranty and I needed to buy another. They asked for the test numbers on the box and they will match. $120 or thereabouts for one tube. I placed the order last night.
1- How common is this … any difference with new quality tubes and new old stock (NOS)?
2 - Why? What is happening in the tube?
3 - Is this the start of a failing tube that could damage my equipment?
I am not at all upset at Upscale… I have been using tubes for … since circa 1988 so I get it… tubes are a drug and a flaky one. However, I never did have one go noisy… usually they just stop working… or like all of them … the slow drip drip drip of neurosis inducing degradation.
Bruce in Philly