Tubes Became Microphonic


About 6 weeks ago I put in some NOS Sylvania 6SN7's into my Rogue Magnum 99 preamp. Just today they became microphonic. Just touching the volume knob caused a metallic sound through the speakers. Tapping anywhere on the chassis did the same. Is this common? Anyone else with similar experience? Is it just a tube issue or something else? I do plan on speaking with Rogue asap but wanted advice/experiences here. thx
ehaller

Showing 1 response by viiu

It can happen to any tube. If the tube makes it past 250 hours it'll probably last it's expected life.

You might want to look at tube dampers. I recommend them but with reservations. They can create a more quiet background although I couldn't say they improve the sound. If they do it's not very much.

On the negative, I think they may give tubes damper memory meaning your tube is more likely to get noisy or microphonic if after having damped it for a month you remove the damper. This can seriously impair your tube rolling.

The reason for using them is that they may increase your tube longevity and may also prevent your tube from becoming noisy or microphonic oin the first place. I've also successfully used dampers to quell microphonic tubes that I would have otherwise discarded.

I'd use them on expensive tubes if I liked the sound and I was pretty sure I was going to keep them, but no tube rolling after that.