Members nuke_diver Posted February 11, 2009 Members Share Posted February 11, 2009 Kind of a newbie tube question I think Are tube lifetimes measured in operation hours, i.e. Preamp tubes last ~ 2000 hrs Power tubes last ~ 1000 hrs (just examples) Or is it entirely a crap shoot as to how long a given tube will last. If I leave my amp on a long time even in Standby will I be using up my time allotment? Sorry if this is a dumb question, I am trying to plan for what replacements I might need and when, the AD30 never had these concerns Link to comment Share on other sites More sharing options...
Members JC777 Posted February 11, 2009 Members Share Posted February 11, 2009 Not really. I've had tubes last 20 years and new stock burn out in 18 months. I'm not factoring in breaking tubes going to gigs and whatnot. Link to comment Share on other sites More sharing options...
Members Prages Posted February 11, 2009 Members Share Posted February 11, 2009 Their life span not only depends on how well the tube was made, but on how hard you push them (for power tubes anyway). If you play with the volume on 10, you'll go through power tubes a lot faster than you would if you played with your volume on 2. I usually replace the tubes in my Classic 30 about every 2 years or so. It's my most played amp. I figure my Classic 50 will get at least 5 years out of its tubes since I don't play it very often. I haven't had my Bassman long enough to go through any tubes yet. Link to comment Share on other sites More sharing options...
Members SDshirtman Posted February 11, 2009 Members Share Posted February 11, 2009 There is really no definitive answer. Its going to depend on how hard and often you push your amp. Pre amp tubes generally last much longer then power tubes. As far as leaving your amp in standby I wouldnt do it for extended periods. How long are we talking? Link to comment Share on other sites More sharing options...
Members benricci Posted February 11, 2009 Members Share Posted February 11, 2009 It's a little tricky to put an actual time limit on tubes. I had a Fender Twin from the 70s that I know was gigged a lot, and still had the original tubes in good shape. Other amps that I've had for under 5 years needed new ones after serious playing time. Link to comment Share on other sites More sharing options...
Members Wyatt Posted February 11, 2009 Members Share Posted February 11, 2009 Their life span not only depends on how well the tube was made, but on how hard you push them (for power tubes anyway). If you play with the volume on 10, you'll go through power tubes a lot faster than you would if you played with your volume on 2.. +1./ Heat is what wears out tubes. The harder they are pushed then hotter they run (biasing can affect this as well). Preamp tubes can last decades because they don't see the same heat as a power tube. Link to comment Share on other sites More sharing options...
Members nuke_diver Posted February 11, 2009 Author Members Share Posted February 11, 2009 As far as leaving your amp in standby I wouldnt do it for extended periods. How long are we talking? Well I did leave it on over night recently but that wasn't really why I was asking. I've got 2 12AU7's 1 to use one as a backup but recently put the 2nd one into the V2 postion of the amp. Now I like the sound but technically don't have a backup in case of a failure (actually I do but they are all 12AX7 of which I know have 5 spares). I do have a pair of Power tubes as backups. Seems like there is no need to rush out and get backups for the preamp tubes which is good cause even though they aren't a lot of money there's not a lot of spare change around and the wife's birthday is coming up Link to comment Share on other sites More sharing options...
Members Armitage Posted February 11, 2009 Members Share Posted February 11, 2009 Preamp tubes last until they start making funny noises or go microphonic. I have tubes in amps that test as new that have been in there for 20 years. Though some newer tubes, like JJ crap-out after 6 months... don't buy/support junk. You can change preamp tubes one at a time. Just change the noisy/microphonic one. They just pull straight out, a little wiggle can help, never turn them. Power tubes wear out based on how hard you drive them. 6 months to a year for heavy gigging amps, years for bedroom rockers. But just because you can bedroom rock a Marshall 100watt stack for 5 to 10 years, doesn't mean you can take it out for a gig after that. It might be just hanging on and ready to burn out. Sometimes when a power tube fails, it takes other items with it! Power tubes are best changed all at once, and it's best to get a matched set. Most amps are designed to be plug and play, but some people prefer to take their amp in to be biased (having the current set for a particular set of tubes). All kinds of people like to argue about biasing, and it's a riot. Most of the people who say you should get your amp biased, are the guys selling the service, but not the guys making the amps. (Though some amps DO need to be biased though). Some guys argue how much better their amp sounds after getting biased... but the truth is, they're usually hearing the brand new tubes in it, and comparing THAT to their pre-biased amp with a different brand of old worn out tubes. Also, once you've biased an amp, you got to buy identically rated tubes as you old ones or you can damage your amp because it may be out of the plug and play range... or take it in to be biased again... and again. And remember, as tubes age... the bias goes out too. I've sat here with tons of guys and adjusted their bias for them, and it's about 50/50, when they can hear a difference, which tone is better, and you've got to be way out, and pretty loud, for people to hear a difference. A correctly biased amp is cleaner sounding (less harmonic distortion). Something else you hear about is a Balanced Phase Inverter Tube... Smoke and mirrors, the circuit isn't balanced. Can you hear a difference, well it's 50/50 in an unbalanced circuit, so just try one of your existing other preamp tubes in the socket. It'll be better or worse or no difference... don't buy a special tube for it because it'll be better or worse or no difference. Link to comment Share on other sites More sharing options...
Members stormin1155 Posted February 11, 2009 Members Share Posted February 11, 2009 As others have stated, it depends on a lot of stuff. Part of it is the design of the amp as well. Blues Jrs. have a reputation for burning through pre-amp tubes. I had to replace mine after one year. On the other end, my '64 Princeton amp still has the original tubes in it, so they are 45 years old. Link to comment Share on other sites More sharing options...
Members nuke_diver Posted February 12, 2009 Author Members Share Posted February 12, 2009 Thanks guys, I don't yet have any issues so I'll just wait Link to comment Share on other sites More sharing options...
Members metallica_00 Posted February 12, 2009 Members Share Posted February 12, 2009 For instance, I do play out, but somewhat infrequently. So my amps are typically running at pretty low effort. Prior to my DRRI, I had a Mesa for 3 years - still going fine on my original tubes. My DRRI is now right around 2 years and I'm still on the originals too. I don't see much point in swapping them out until I notice a change (for the worse) in sound or issues like microphonics etc. Link to comment Share on other sites More sharing options...
Members wagdog Posted February 12, 2009 Members Share Posted February 12, 2009 I think some changes are incremental, over time so it's hard to notice. I gig once or twice a week and practice once a week, plus practice at home. I replace all my tubes yearly, whether I think they need them or not. Link to comment Share on other sites More sharing options...
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