November 2nd, 2009 | 
Author: I’m pretty sure I’m going to buy the Peavey ValveKing 112 (http://guitars.musiciansfriend.com/product/Peavey-ValveKing-112-Combo-Amp?sku=481442) but I’ve heard some things about tubes going bad and i really know nothing about the tubes in a tube amp. It would be great if someone could explain to me how the tubes work. But more importantly, is there anything i need to do to keep the tubes alive and working well?
Good points in the preceding answer, if you bang it when moving it or have a drive over rough road be sure to check that the tubes are pushed in all the way before turning it on. Put it on standby if you want to leave it on for a while but aren’t going to play it.
Posted in tube amps
Read the manual. It will tell you to turn on the warm up switch first, and then the power switch.
Other than that, your amp will last a long time before needing tubes. At some point the power tubes will likely fail, or the bias. But in the Peavey, the bias can be adjusted easily and the tubes replaced as well (make sure you have it done by a professional of some type).
Other than the obvious, like treat the amp like it was a baby, there really isn’t anything special you have to do than the above.
References :
Good points in the preceding answer, if you bang it when moving it or have a drive over rough road be sure to check that the tubes are pushed in all the way before turning it on. Put it on standby if you want to leave it on for a while but aren’t going to play it.
References :
Other two answers were good.
Tubes don’t go bad nearly as much as people like to think. Properly care for your amp and you’ll be just fine… which means doing things like having the amp on "standby" when you power up, power down, and when you want to walk away from the amp for more than 15 minutes. When the amp is on, always have it plugged into a speaker. Swap out your power tubes every 2-3 years, make sure they’re matched. Preamp tubes don’t really go bad, but its always nice to get new ones and try out different tones that different brands/models of tubes give you.
If you need/want to replace the power tubes, usually the amp will need to be rebiased. Its easier for an amp tech to do this for you, unless you have researched it extensively, have experience with electronics, and know how to work with high voltage without shocking the living #^$!( out of yourself. No re-biasing needs to be done with preamp tubes.
Watch out – tubes heat up fast and stay hot for a while – be careful when handling!
Its best to not leave your amp out in the garage, or places where temperatures vary and/or there’s lots of humidity. Honestly, this is common sense stuff that should be applicable to *all* of your guitar gear, but whatever – needed to be said.
Its a good idea to have a backup set of tubes. You will probably never need them, but if you do it’ll be a life-saver.
The simplest explanation of how a tube works is that a tube acts like a switch – a small amount of voltage controls a larger amount of voltage. Think of it like crimping a garden hose – with a little bit of effort you can control quite a bit of water… its like that. The voltage hits the grid, and that controls how much power flows through the tube (like water through a hose, really).
Well, it’s a little more complex than that, but the important thing is that a little power can control a lot of power…. that’s why its called amplification. =)
There’s a great link below. Read it! It will answer all of your questions, I think.
Saul
References :
http://www.geofex.com/tubeampfaq/taffram.htm