How do you know when to change the tubes in a tube amp(guitar)?

Visual check? take them to a tester?How do you know when to change the tubes in a tube amp(guitar)?
There's a couple of ways that you can check whether your tubes need changing....



Firstly, if they've blown, then you'll know they have, as your amp just won't sound the same as it did, the day you bought it.

Basically it'll sound really bad, and lets say, if it sounded that bad the day you bought it, you wouldn't have done, if you see what I mean. There's also some signs, like lack of power/volume, etc.



Secondly, there's a little test that you can do, where you switch your amp on, warm it up, then get a lead pencil and tap (gently) the bottom (nipple end -sorry, best way to describe it) of the valve with the butt end of the pencil, if there's a sort of clunking/nosiey sound, then they've blown and need changing.



Also, they might just be a little loose, so you could check how tight they are in the socket.



But, basically if your amp doesn't sound as good as the day you bought it, then it needs servicing, and it could be anything, from something simple to something fairly complicated.



Hope this helps you out!!How do you know when to change the tubes in a tube amp(guitar)?
In the old days (I only know them from tv's when I was little) old tubes were black inside and made sqeaking/buzzing noises.



But in amps these days its when you dont like the sound anymore you change them.
take to a tester good luck finding one

every corner store and electronics store had one