Replace tubes yearly?

The life of a tube is greatly dependent on the type of tube, the operating conditions of the tube, and even the specific manufacturer of the tube.

Power output tubes tend to have shorter lives than linestage tubes or the input and driver tubes of an amplifier.  Even among output tubes, the ones that are called upon to output high wattage tend to have short lives.  A lot of manufacturers, in order to claim high output, create operating conditions that mean shorter life than if they backed off a bit on those operating conditions that shorten life.  

While the smaller signal input and driver tubes tend to have a longer life, these too vary greatly in how hard a particular amp drives the tube.

Given that there are so many variable involved, there is no simple formula, such as change tubes after this or that time interval.   Both my amp and linestage drive my tubes so gently that I have not had one tube go bad in over 15 years of operation.  Even at the start of my use, the tubes that were put in were used tubes of unknown prior usage.  Most of these tubes were probably well used before I got them.  But, all my tubes are run so gently, they are expected to last a very long time.  This is a VERY good thing because they are all expensive.  My output tubes are 349s, the driver tubes are 348s; my linestage tubes are 310s.  

If you want really warm, and have deep pockets, I would say look for 5692 tubes.  They are drop in substitutions for 6SN7s.  My Audio Note Kageki amps came with these tubes, but I fooled around and ended up with Tungsol Roundplates which are not as warm sounding but I appreciated the greater clarity.  

So, a maker of solid state gear, and only solid state gear, states that if you buy tube gear, you have to make yearly tube replacement.  Does anyone think it is a scare tactic?  What if I say something completely unsupported like, “you shouldn’t worry about your PS Audio amp catching on fire, that is what insurance is for.”

That they have input tubes that require yearly replacement should be a good reason NOT to buy that gear.  Clearly, they don’t know how to implement tubes in their design.

The primary reason for leaving solid state on all of the time is because transistors will not degrade nearly as quickly as will tubes from constant use and solid state gear takes much longer to warm up than tube gear.  The primary downside to leaving solid state on all of the time is that this exposes the gear to more mishaps, such as powerline surges and brownout (undervoltage can be particularly hard on solid state gear) and weather-related mishap.  Also, while transistors have a much longer life than do tubes, they are not nearly as easy to replace, and it is sometimes the case that there are no replacement parts available many years later when they do need replacement.  By contrast, most 80 and 90 year old tube gear is easily serviceable.  

Which tester to buy and how to interpret the results is a very complicated subject unless you are just looking for rough results, like avoiding shorted tubes or dead tubes.  I had tubes that tested very weak on an Amplitrex (modern, industry standard tester) but still sounding good.  I contacted the amp manufacturer who said that in this particular application weak tubes would work fine and I should use the tubes until they sounded bad or died.

If you use tubes that will eventually need replacement, get a complete set of replacement tubes.  You can "test" the old tubes by swapping in tubes from the reserved set; if the sound improves enough so you are willing to replace the old ones, you already have the replacement(s).  This subjective testing is probably more meaningful than most measurements on a tester.  

Remember: all old and worn out tubes can be sold on eBay (just kidding, throw them away).

I have, and like, the Amplitrex tester.  It is simple to use, tests at full power so the tubes are measured under stress, and it displays both test measurements and the specified values to compare the results to.  But, one still needs experience to know what the results mean as to whether or not the tube needs replacement.  The biggest downside to this unit is that it is expensive.  There are kits for testers that experienced tube professionals like.  One expert who owns well north of a dozen testers, including several Amplitrexes said that his favorite is the kit called the e-Tracer out of Taiwan.  Hooked up to a laptop, it will curve trace the tube (the Amplitrex can do that too).

Since I’ve settled on my current setup, about fifteen years ago, I’ve only had to replace two tubes and that was because a shelf collapsed and dropped my turntable motor controller on the power supply of my phonostage (it uses two 300b tubes as rectifiers).  Other than that, not one tube in 26 that are in my sysrem has gone bad.