general amp maintenance - new to this

[piper19]

Hi all, I want to know what maintenance a tube amp needs at what times. I always did bring my amp to a tech, but I think I'm paying too much for nothing special done. (80 euros for putting in 1 of their cheapest 5AR4's + 3 weeks without the amp, I can do this myself I think).
Now, my amp is a hotcat 30, which is cathode biased. This means I can put in any matched pair of EL34's without any biasing or adjustment, right? Or anything else I need to know? I found a nice pair of Mullard reissues.
Same for the 12ax7's (any recommendations?) and 5AR4's I guess (found a NOS Mullard 5AR4).
I also read something about filter caps on this forum. When has this to be done?
Thanks dudes:RoCkIn

[phsyconoodler]

I don't know what a Euro is worth in Canadian funds,but that does sound high.It depends on what was done.Labour is what you pay for.
With your cathode biased amp,you can change tubes to your hearts' content.No biasing needed.
Filter caps should be changed on average every 10 yrs or so.They keep the amp in perfect working condition.

[Dave C]

80 Euros=$110 US or $115 Canadian. The last Sovtek GZ34 I bought was $13. I don't know what else your tech did so I won't say he overcharged you , but many maintenance tasks you could perform yourself.

I'd suggest you get a multimeter and a bias probe and some other tools and learn to do this for yourself. It can be very educational and rewarding to fix your own amps. Most importantly get some education on how amps work and safety precautions for working on them because they do operate at lethal voltages.

Cathode biased amps don't require "biasing" as such ,but current draw still should be checked anyway because tubes aren't created equal especially modern production stuff . Cathode resisters can be changed to accomodate tubes with different current draw.
Dave C