Some Nice 6L6s

[shimmilou]

Probably depends on the tube, but it sounds like a high frequency jingling or ringing sound when I've heard it on any of my amps...

Les, seems as you are describing a microphonic tube, which is different than rattling, although both are faulty tubes. Rattling is more as I described above.

 

[Boogie]

It's more likely with combos than heads, due to the tubes hanging right next to speakers. A separate cab and head isolate the tubes a lot more, though there have been times I've gotten tube rattle even with a separate cab and head.

To get the most life out my tubes in the SuperD, I’d put the head on the floor under the cab. Got tired of changing tubes.

 

[László]

Les, seems as you are describing a microphonic tube, which is different than rattling, although both are faulty tubes. Rattling is more as I described above.

No, I'm describing rattling, which I perceive as different than microphonic, YMMV. I know the difference. Vibrate anything against a small vial of glass and you get a high pitched ring.

In fact, shake a tube prone to rattling and you can hear it when it's not in the amp.