The main reason tubes don't last as long these days is they are not pumped as long (see tube article post here somewhere). In the old days tube makers had their own metallurgy sections also to play around with different alloys etc for cathode anode etc. But longevity (as long as the tube is used within specs) is more about the vacuum (like a light bulb, they can make them last forever (ish) and do for ships by pumping more/better vacuum to handle the vibrations). Also on/off hot/cold cycles have an effect (not just on tubes, but all components). The amp makers (the biggest consumer of tubes) have no reason to have tubes last a long time, for them it's good if they can sell you some new tubes every year or two.
Original ADA tubes were specked (in ADA manuals) IIRC to be changed MP1 ~ 2 years, and MP2 ~ 1 year. Also the manual notes to let your tubes cool down before you move the unit.
My personal experience, the original Chinese tubes in bot MP1 and MP2 lasted for ages (so very well pumped, well made), the Boogie STRs I put in the MP1 we only just changed out recently (though it spent some years in storage while MikeB was in London), although the old ones still work fine.
Also tubes go off slowly so you don't really notice until you put in a new set (e.g. MJMP changes his 3TM tubes every couple of months or so to keep the sound/edge he likes).
An interesting point SC makes is the more articulate tubes are less forgiving (as in track every little nuance of your playing), I like this aspect, others may not.
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Topic: New Tubes Advice (Read 115425 times)
