Replace tubes yearly?

As OP I have nothing to add to the great technical advice given in this thread.

I do wish I could remember which Audiogon member sent me those tubes a few years ago. It was a very gracious, and trusting, thing to do for someone he’d never met anywhere but here.

I will also say that in the last year or so I get a little bit of speaker hum when I first turn my system on. It goes away to complete silence after about 5 minutes. This is an old system so I guess it could be anything but it makes me wonder if it might be a tube. I may get a back-up set just to test it.

But, I confess that I absolutely hate messing with my system, fooling with cords and pulling components out. I guess some people enjoy that but I don't.

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).

I wouldn't know what once a year is since random tubes blow at different times, and I don't keep track. When a tube blows I replace it. In my ARC gear some tubes doing the same work as others (output stage, for example) blow much before the others. I buy the same brand of tube and do not really hear the difference when I replace one tube in a pair (output, input, etc.) and I'm listening to an old paired with a new. I guess I'm a lazy audiophile or else I'd have a chart and keep track.

The adage, if it ain’t broke, don’t fix it ... comes to mind

I will often leave my Allnic Audio A-6000 300 BXLS tube amplifiers on 24 seven they are on at least 12 hours a day every day for the last five years, I have an AT-1000 Amplitrex tester, they are still testing in the low 80% range.

the amplifier has bias adjustment metering for each tube, I check it daily and have never noticed any kind of drop, it goes up or down a little based on AC coming out of the wall, but that's about it

Bottom line ... every circuit is different, every tube situation is different, if the amp sounds bad or the tube goes bad, you will notice, if you didn't notice, then everything is fine. 

I have been using tubes for 56 years so you would think that might make me an authority but I will make no such claim. Just my experiences, these are what they are:

I used a Dyna Stereo 70 and the Dyna MK IIIs for 17 years. The tubes tended to last for 2-5 years. I think for the Stereo 70 those are the 7199 and the 5AR4 and one or two others, for the MK IIIs those are 6550 and a 6AN8A, and there’s maybe another? I am having difficulty remembering.

I switched to the NYAL Futterman OTL3s in 1985. For 10 years, they were a little unstable. One meltdown was my fault: I experimented with a pair of Duntec speakers that caused the caps to liquify, 😂.

But for the last 30 years, I have gotten 15 years (not a typo) out of the 6LF6 tubes. I just refreshed them last year with a completely NOS set of GEs. The tubes that got replaced still had 65% of their juice in them. The little tubes in the back have been replaced maybe once the entire 40 years that I have relied on the amps. I asked Jon Specter if I should replace them along with the 6LF6 tubes that got replaced last year, he said not necessary.

I replaced the tubes in the DYNA PAS preamp maybe twice during those 17 years. I have replaced the tubes in the Beard P505 preamp 3 times over 40 years. This last time, last year, the Beard got serious NOS Telefunkens, Mullards etc from the late 1950s / early 1960s.

The caps in the Futtermans got replaced in the mid 1990s, as stated, and again, when I replaced them just last year (along with the tubes), after 30 years of use, they were quite dried out and almost at the point of failing. I switched from the photoflood caps to three big mofos, I don’t know what they are but they are faster than the photoflood (the photofloods were the fastest back in the day, so I’m told), and more robust, especially in the bass.

As for on/off: the Futtermans get turned off at the end of the day. They are rarely running for more than 6 hours at a time, ever.

The Beard is left running 24/7 unless I am away for several days.

The Project phono stage is also left running 24/7 unless I am away.

As for tube-rolling: some tubes will sound different but not better. Some old tubes can sound better than new tubes. Some cheap tubes can sound better than pricy ones. I just had a situation where a cheap $50 Raytheon sounded better than a $350 Mullard. It’s system dependent. Trial and error.