[hvu]

I just got new 396a WE tubes for my Tu-882 amp.
When I plug in the headphones, tap on the case "not the tubes" or tap on the table that the tubes sits on I get weird pinging noise like when you hit a metal pipe with a stick.
Are my tubes broken?

 

[Zombie_X]

They are microphonic, and no they aren't broken. This is common among tubes and it's just them vibrating and creating noises. You could try tube dampers on them and this should help. If not you should return them for new ones.

 

[hvu]

Since these tubes are brand new tubes would exchanging them for new tubes solve this issue or would they all be the same?

 

[BigTony]

Rule No. 1 about Tube Club : Patience!
Tubes often howl, whistle, click, clunk and humm when you just put them in - so the best thing is not to worry, drop them in, and leave them to get used to there new home. If after 24 hours of running they are no better, then you should consider further action, tube dampers can be helpful etc; but best not to panic, give them time.

 

[Skylab]

Those tubes are microphonic for sure, that doesn't mean the tubes are "bad". ALL tubes are microphonic; it is just a question of degrees. If the tubes are not otherwise noisy, and it doesn't bother you when you listen to music, then it might not be worth worrying about.

 

[hvu]

Thanks you for the replies.
This is my first tube amp and first time experiencing microphonics so I'm guess I'm paranoid but I am enjoying them now

 

[Seamaster]

Also some tubes are have constant noise, I had a pair of Mullard do that, but after about 10 hours the noise are gone untill I change them next time