regardless of brands and models, mahirap ba ang maintenance ng tube amp?
unlike solid state amps na walang iniintinding valves. . . gano katagal ba ussually bago na burn out tube?
locally at readily available ba mga tubes?
for me, the maintenance of a tube amp isn't that much harder than a solid state amp.
first off, you need to know that a tube amp has power tubes and preamp tubes. if the preamp tubes are good, they should last you a long while (e.g. upwards of a year to indefinitely) unless they go microphonic. the replacement of preamp tubes is simple. just plug in the replacement tube and play.
power tubes, on the other hand, are a bit more complicated. generally speaking, the lifespan of a power tube depends on the following:
1. quality of tube (better tubes = longer life)
2. the frequency of use (more use = shorter life)
3. how often you crank the amp up (cranked more often = shorter life)
4. how hot the amp is biased (hotter bias = shorter life; colder bias = may affect tone negatively)
5. type of power tubes (the most common families are 6L6, EL34, and EL84. 6L6 and EL34's are not interchangeable unless your amp specifically allows so, while EL84's are definitely not interchangeable because of different pin configuration. EL84's are less robust than the other types.)
now, let's assume the tubes are good. with frequent use at max volume (e.g. almost everyday), the power tubes will last about 3-6 months at the most. on the other hand, if you are a weekend warrior who plays at moderate volumes, your power tubes should last you a year upwards.
the common tubes are readily available at audiophile and other audio shops.
let me share my experience. when i first got a tube amp (sometime during the mid to late 90's), i was also a bit apprehensive, asking all the same questions you did. to make a long story short, my concerns were unfounded, the tone was worth it, and i'm never going back to solid state.
cheers.
