Why and when maintain your amplifier ?
A tube amp deteriorates over time.
Deteriorated sounds, artifacts, decreased performances... It seems like your amp don't like you no more...
No reason to panic, while it work at least a beat. There's a strong chance that a maintenance operation can restore it to its initial state !!!
Maintain an amp means proceed to a rigorous test/check of some key components (tubes, but not only that), witch impact sound measures (audio power and sound quality/caracteristics).
Have your machine maintained could save you from buying a new one...
If you consider you are (could be) in this situation, send us details about observed deficiencies and kind/trademark/model of suspected system.
If a checking or maintaining operation appears to be needed, next step is shipping material (freight charges at your expense) in order to analyse it and identify the technical needs. After analysis, you receive a offer and work schedule with proposed start and end dates.