New tubes every year...or every five? ?

I may get thrown off this forum, referred to an ear specialist and sent to Circuit City to replace my system, but it recently occured to me that I did not change the tubes in my recently dumped Jadis JPL pre amp for 5 years! There is no on/off switch on this pre amp but there is a "stand by" switch which was always on. I would say I listened to the system for only an hour or so a week. Since trading my Apogee stages for Martin Logan SL3's about 3 years ago, I rarely listened to the system and found it uninvolving and a little fatiguing and bright. It didn't necessarily sound bad -- I thought I just needed to buy a new D/A or go back to LPs. Is it possible that my very light use and the standby switch would give the tubes such a long lifespan or would a change of tubes have dramatically improved the sound? Maybe I should have kept the system?!? Oh well, more fun to buy new stuff...
I don't have enough experience with the Jadis circuit to know whether the tubes could survive that length of time or not. I did have a similar situation with a Counterpoint SA9 phono stage that was left on (NOT just standby) for 24/7. During a storm, a roof leak and water entering the chassis made repair necessary. This occurred almost exactly 4 years from the day I bought this unit and first turned it on. The repair was made to a section of circuit board and a small cap, but the factory gave a clean bill of health to all the tubes! Obviously this would have been a great time to sell me a new set, so I must assume they indeed ran all that time without enough wear to sabotage the factory test specs.
CWlondon, hi! I have a Jadis front end for about five years now. I listen dayly from one to three hours plus one hour warm up time. I use Telefunkens salvaged from old gear, however paired and measured for noise in my headamp and the phonopart in the pre. Never changed a tube so far. The other day, after a cleaning frenzy, I put in a back up set of the same tubes just for a try and listened a whole Saturday afternoon. Afterwards I happily put my old set back in. Now the question arises: Is it the Telefunkens, is it the Jadis design or should I have my ears examined?
Cwlondon, Detlof & others, we'll get a quantity discount for the examination or the hearing aids... I had a Jadis front end with Sylvanias. I sold this back in 1991. The buyer subsequently sold to a friend of mine and, there I was, staring at the same old Jadis about two months ago. Same old Sylvanias, too. Now how about that... (my friend does have a set of brand new Golden Dragons sitting in a drawer)
In my experience, when a preamp needs a new tube, you'll know it: noise, tube 'rush' etc. Not subtle. Plus, don't you have access to a tube tester?
Hi Gregm, what a great story! What we should probably get, is a tube tester with the necessary charts, then we could objectify what we hear. If remember correctly, there was a thread also about Jadis and the Aesthetix Io where Albert Porter told us, that he also had his Io switched on 24/7 and that after a year he remeasured his tubes with hardly a change for the worse. Memory may trick me here, but I think that was the gist if his message. Great thread, by the way!
Musicslug, true what you say, but then there is also tube aging with its slow and gentle deterioration, which is indeed hardly noticable. Generally you only realise the need for change when you have indeed done so. That's what's bugging us. So right you are, all the more there is need for a tube tester. Not for compulsion neurotics though, because they might test tubes more than using them for enjoyment. All the same: Anyone got an idea of a reliable source for them ? (t.testers..not c.neurotics)
I'll add that I've had the same Telefunkens in my JP80 for almost 3 years, and usually leave it on 24 hours a day from Wednesday or Thursday through Monday (it used to be just for the weekend, but that's been expanding). Last time Andy Bouwman made a check on these tubes after 1-1/2 years they were all hardly changed from when I first bought them. The exception, and not applicable to the JPL, are the two 6DJ8s for the MC stage, which go bad after a year or two; the JP80 pushes those tubes to the limit, I guess. George Kaye here in NYC made a small signal tube tester a number of years ago that sold in the $500 range--I don't know if it's still available. And Detlof, I think we all know a reliable source for neurotics....
Hi Cw; I have a Sonic Frontiers Line 2 with 6 Sovtek 6922 tubes. I typically listen 4-5 hours/day, and also broke in some equipment using the Line 2-- leave it in standby the rest of the time. After about 16-18 months, my system gradually was sounding brighter, harder, and distinctly more fatiguing. It finally got to the point where I could hardly stand to listen to it. Then it finally dawned on me that I had NEVER changed my pre-amp tubes. Duh! After installing a new set of stock Sovteks-- Viola', the music came back. I had thousands of hours on those tubes, and really learned a valuable lesson. I now replace them about every 12-14 months. Cheers. Craig.
Hi Garfish, this is just a guess, but I think its probably the Sovtecs and not the SF. My experience has been, that Sovtecs seem to age rather quickly with exactly the sound-effects, which you describe and this not only in the Jadis, but also in the Beveridges of yore, a wonderful design by Roger Modjeski, which was killed and driven off the market by a hatchet review of H.Pearson in favour of the ARC SP8, in the SP 11 and 12.
Craig, Detlof's probably hit it the proverbial nail on the SOVhead. The current supply on (my) Jadis was quite stable and ample, hence no extraordinary tube wear. But replacement every 12??? That's expensive -- why not try another tube manuf. and if you feel the top end is soft by comparison -- don't worry: this could be cable or the machine... Just an idea.
Detlof Check out e-bay for tube testers. My audio buddy just bought one from a guy that restores and calibrates them. This past Sunday we went through about a quarter of my stash. What is most amazing to me is how the old tubes fared against the sovteks and newer tubes, all were MUCHO stronger. I have a bunch of amperex and the old Bugle Boy's and some Telefunkens, RCA's and Sylvanias. Only one of the old tubes was shorted. Two of them buried the meter! A few of these tubes were in my McIntosh MC-60's dating back to the mid 50's!! I also found out that the Svetlana 6550 output tubes I installed in my amp a year ago still tested strong with plenty of life. I estimate that they have about 1200 hours based on my use. It is a nice thing to know and you can keep your equipment running optimally. I say at the cost of tubes these days a tester is indispensible. I plan on purchasing one in the near future.
Detlof, my tube guru Andy Bouwman has some tube testers he keeps available for sale as well, and the prices were not high. I'll probably pick one up, although I can always send him my tubes for testing, since I buy from him.