newby question on tube degeneration...

[carlsoti]

My Rocket 44 was purchased new sometime near or before 2000. It has worked perfectly up until I pulled it "out of mothballs". It seems to be hissing when not being played much more than I recall it used to.(it's not been used in 8-10 months) Do tubes "go bad" when just sitting? I've never gigged the amp, so it's not really been used that much. How long should the tubes last? Could it just be old tubes making the amp "more hissy" than it used to be? Could caps dry out this soon?

 

[Russ]

I don't think that the caps would dry out this soon. I am more under the impression that the hissiness is being caused by your preamp tubes being noisy. They don't go really bad while sitting though. Typically they get the most wear for use or shock like from transport while the tubes are hot. I would say that if your amp is 7 years old it could stand for a retube being you used it for 6 years. Current preamp tubes can last a year or two under moderate use. Daily is more like 6 months. Power tubes last about twice as long as preamp tubes in general. But you can also get bad tubes straight out of the box.