This ultimately depends on how often you play. The more often you use your amp, the more often the tubes will need replacement. They simply wear out over time. You can hear the difference when your tubes need to be replaced. The amp will start to sound dull and lose the punchy, crisp sense of clarity it once had. If you never play the amp, you may never need to replace the tubes. But what fun is having an amp if you never play it? If you are very active and practice about 2 times a week with a gig once a week, your tubes will probably last around 2 years. The variables that contribute to wear on your tubes are: turning the amp on and off, how hot the tubes get after hours of operation, how hard you push them by turning up the volume on your amp and driving your tubes hard for an extended period of time.

When it comes time to replace your own tubes, here is what you need to know: Depending on the manufacturer's warranty, you may need to have an authorized service center replace your tubes. If you replace the tubes yourself and make a mistake, it can void the warranty. However, most manufacturers are okay with the owner replacing the tubes, or taking the amp to a local shop that isn't authorized. Pre amp tubes are very easy to replace and aren't too technical. In almost every case it is a matter of buying the same type of tube (you can make a substitution in some cases) and popping it into the socket.

With power tubes it is more technical. It is recommended that a certified technician take a look at the amp and replace the tubes in case the amp needs to be biased. If the amp needs to be biased and isn't, you will end up burning up the new tubes very quickly. You also run the risk of seriously damaging the amp. You can avoid the need for rebiasing if you are installing power tubes with the same hardness rating as those being replaced.

Here are some important safety tips: Remember that a tube amp possesses a great amount of voltage. It can kill someone! The filter capacitors in the amp will have some charge left in them after the amp is shut off. Taking an insulated jumper from a grounded point to a plate lead on a pre amp tube should eliminate the excess charge. If you are not certified, or very familiar with electronics, please do not try this alone. You can read the manual to get more info on safety and precautions. They may even have detailed instructions on how to replace the tubes yourself.