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Help with tubes

Discussion in 'Amps and Cabs [BG]' started by jellybass, Nov 9, 2005.


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  1. jellybass

    jellybass Guest

    Nov 8, 2004
    I am considering a tube amp for the first time, specifically a Mesa/Boogie Buster 200. Having been a solid state guy all my life, I know nothing of tubes and I am looking for help. How long does a typical tube last? How hard is it to change the tubes? How hot do the tubes get and how long until I can touch them (cool down time)? Are 200 tube watts louder than 200 solid state watts? Also, if anyone has any experience with the Mesa/Boogie Buster 200 then let me know what you think. Thanks.
     
  2. Tubes can last a very long time, I've got one amp with 40 year old tubes.

    Tubes are easy to change, if you decide to change them. No special handling required, you can handle them with your bare fingers. Takes them about 10 minutes to cool down.

    Many people say a 200 watt tube amp sounds like a 300 watt solid state amp.

    I played through a couple of Busters at the store a couple of times, they seem like good little amps. The combo versions are heavy though.
     
  3. jellybass

    jellybass Guest

    Nov 8, 2004
    Thanks, that pretty much answers it for me.
     
  4. Just to add to the tube life time bit, my SVT had the original tubes in it when i got them changed earlier this year, and it was made in '89 and used as a workhorse amp, did ALOT of gigs and festivals (was rented out a few times too), so thats 16 years before one of the tubes went bad, the pre tubes were fine but i went what the hell and stuck some higher quality ones in too

    Hope to not have to retube for another decade at least :)
     
  5. specplyrz

    specplyrz Banned

    Nov 11, 2005
    Well, you can belive the "20" year old power Tube stories all you want. Any high power amplifier that is used ALOT 2-3 hrs a day five days a week, will need the power tubes replaced, between 18-24 months. Sooner if the amp is set up and tornd down alot. Yes therew are 20 year old tubes out there, still working, but they are the acception to the rule. Many sites on the web, tube manufactures as well as amplifier manufactures, reccomend replacing your power tubes at the first sign of trouble, (softer in volume, mushy sound, odd noises).

    Tubes are like tires, the more you use them, the quicker they wear out. Drive slow and once a week, and tires WILL last 20 years. Common sense is the guide here.
     
  6. popinfresh

    popinfresh

    Dec 23, 2004
    Melbourne, Aus
    Umm, I was always told it's bad to touch the tubes bare handed?
     
  7. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    A common set of tubes (for the Buster) should last about 5 years. And as for the question of volume, multiply the watts by 3 or 4 and you have a comparable volume in SS watts. You can touch tubes bare handed, just dont toss em around :p
     
  8. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    Just recently started messing with a tube amp and it's a different world. Warm up/cool down. Matching tubes. Amp is biased for certain tubes. Different response to wrong ohm cabs, different response when cab is inadvertantly disconnected. I would want at least one backup for each type myself. I think of them like lightbulbs in that sense although it's not extreme like that. I guess it could happen but from limited experience so far it looks like the wear is progressive and they don't blow out at once like a lightbulp. You'll probably know when they're going south but that doesn't mean that won't happen in the middle of gig. Tube type/make/condition alters tone.

    No doubt some tubes are a lot more difficult to get to in some amps than others and even different ones in the same amp. But they're made to be changed.

    I only change before I fire up so not sure how long it takes them to cool down - 5 minutes maybe. Probably more for power than pre and if the amp and in environment are a lot hotter - like a car engine cooling down. I'd think a pair of surgical gloves or even snug laytex dishwashing gloves would permit pretty quick access. Tubes are glass so you'd want somethng that would grip otherwise they'd be easy to drop/hard to control. Much less of an issue in putting them in than pulling them out. Off the cuff I can't imagine anything (tool) besides your fingers that would work as effectively.

    Never heard about not touching them with your fingers but I know I try to stay off the lettering cause it wears off. That's not a typical issue cuase contact is an isolated occurrence in most situations.

    Another thing to the uninitiated is there's a bit of a unique feel to changing tubes - pulling them and to know when they're seated, each of which has a VERY different feel to it. If you change a set out it might be a good idea to start with smaller preamp tubes and pull and replace one at a time instead of pulling them all them replacing them - just to get a feel for the difference. Probably the easiest access and most voluntary ones at that. In other words, if the first one gives you trouble, try another then go back. Also, if you can see to, inspect them to verify they're seated properly (which I assume is flush with the base).

    I probably changed a dozen tubes before it felt comfortable - even then there are exceptions. Looks at the pins first to make sure they're straight and to get an idea of what your working with.

    Changing tubes is no big deal but it did feel awkward and unnatural to me initially.
     
  9. carrying spare tubes around is a good idea, but flawed, in that the tubes in your amp have more protection than ones just getting carried around, so if one went out in your amp, and you stuck the backup tube in, chances are the backup tubes dead aswell ... oh, and thats just for pre tubes

    replaceing a single unmatched power tube could be just asking for trouble :rollno:
     
  10. Also, i was recommended to let my amp warm up for about 5 minutes . . . but a cool down period? you dont need that at all IMO
     
  11. luknfur

    luknfur

    Jan 14, 2004
    DIXIE

    FWIW:

    that may be but that's what THD recommended a warm up and cool down of 2-5 mintues in the manual and that's what I have. Don't know about others but I was assuming there was some parallel which their may not be. Also it seems that tone can change for up to about 20 mintues till the tubes get good and hot - maybe just me.

    I also assumed that the replacements would be from a matched set but then I guess it wouldn't be matched any more when the other tubes wore. Which is another good point to raise regarding idiosyncrasies of tube amps. Also some amps have some kind of self-biasing in them which I guess would compensate somewhat - but biasing is not something I have a grasp on. The configuration of your amp also seems to factor in to how receptive it is to tube mixes, various biasing.

    What I do know is no tube, no sound (at least with my amp). So personally, I would always have backups. Mine sat for a couple of days when I first got it (used) cuase one of the pre tubes was shot and I had no others - that won't happen again.

    Tubes are a different world.
     
  12. Why? What quantifiable entity 'wears out?'

    Again, why?

    What 'rule?'

    Yes, you should believe everything you read on the internet. :rolleyes:

    Tires wear tread. What 'wears out' in a tube?

    Nope. That's not true.
     
  13. Backups are fine, but not for carrying to gigs, and if you put in an unmatched power tube, it could draw more or less power than the others in the same set as it, making them burn out faster or it burn out faster, however, i spose if you replaced a whole set of tubes from the power setion (say 3 of the 6 or whatever sets your amp uses), and replaced them it would probably be fine, aslong as the bias wasnt too far off ?

    Warm up is needed because the tubes work optimally (or properly at all? ) at temperature, thats why they have heater elements in them, but why would you need a cool down period?

    I mean, its not like turning the amp off once its stopped sound cming through (when you switch you standby there is some residual charge in the caps that gets used IIRC), but after that you can just turn off, i dont see why leaving it on standby (ie with the heaters on) will cool it down, because, it wont, it'll just mean the temerature will be the same as what you had warmed the tube amp up to when initially turning it on, and its not like the tubes are so hot that they will cool unbelieveably quickly and the glass will shatter
     
  14. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    I'll follow-up on the cool down thing from the manual. Could be I go the idea elsewhere. It's been an inconvenience at times and I'd personally as soon eliminate it.

    To date I've just gone under thoughts along the line that the tubes run hotter with a load than not so it made sense enough to me that gradually decreasing the temp was the flip side of gradually increasing it. Plus that, this is really just an experimental setup for me so the norm is to be turning the amp on and off frequently rather than running for extended periods which is what most guys would be doing. So my tubes I assume will have a shorter life span just by virtue of the application.

    Pulled up the manual. I can't give the exact wording cause it won't let me cut it but paraphrasing it said:

    to allow the tubes to cool more gradually and to decrease the possibility of internal arcing.

    Just another aspect about tubes. You hear all kinds of debates over given issues with tubes that don't seem to exist with SS amps. Comparatively to me, SS amps are plug and play. You don't have to know much of anything. That's a plus in my book but it ain't the same sound and I'm having a blast with this little tube amp.
     
  15. specplyrz

    specplyrz Banned

    Nov 11, 2005
    Tubes DO GET HOTTER when in use, (not in standby)...the voltages that tubes use are extreme.

    My SVT CL when in standby...puts out very little heat from the fan...start playing, and that fan temp rises quite a bit from the high voltages being applied to the tube. In standby, there is no high voltage to the tubes. People say you can turn your amp off straight from playing, but the manual as well as many articles state, use standby.
     
  16. specplyrz

    specplyrz Banned

    Nov 11, 2005
    Tube Replacement Basics

    There is a lot of hype floating around about how often tubes need replacement. As a result, too many good tubes are replaced unnecessarily, and not always with better quality tubes. Let's strip away the hype and take a closer look at this important subject.

    Tubes fail for three basic reasons. They wear out, short, or become gassy. In the case of wear out, here's what happens: If you look inside a lit tube, you will see a glowing red stem in the middle of it. This is called a cathode sleeve. The manufacturer has coated the outside of the sleeve with a proprietary white powder, which emits electrons, making tube action possible. The sleeve is heated to incandescence by a coil of insulated wire stuffed inside called a filament. Your amplifier powers it. . Heat causes the powder to deteriorate over time and emit fewer electrons. Tube performance dies with the powder. Shorts are caused by excessive heating of the elements, which causes them to warp and touch. Power tubes and certain small-signal types such as the 7199 are prone to shorts because of internal heat build-up. "Gas" refers to air molecules, which have forced their way inside. This is typically caused by a faulty glass-to-metal seal, where a wire passes through the glass envelope to the tube element. Gas is bad news because it causes the tube to conduct more heavily (run hotter), reducing its life


    http://www.tabcrawler.com/articles.php?action=readarticle&articleid=78

    "Tires wear tread. What 'wears out' in a tube?"


    You now have your answer. :D
     
  17. Im not sure how it could cause arching, yeah, i know that the tubes run hotter when being used alot, thing is, the temperature will drop at a safe rate, i never switch straight off, always to standby, and hit the strings till theres no sound coming out then turn it off

    PBG will be able to enlighten us :)
     
  18. IIRC, at normal temp (ie aslong as the tubes arent burning too hot, as i've had before), tubes wearing out as you described is quite unlikely, they have a crazy lifespan, somewhere in the region of 10,000 -> 20,000 hours again . . . IIRC
     
  19. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    One thing I've already experienced with tubes is that not only different tubes but tubes in different states of wear produce different tone. At least in terms of tone alone, I can definetly see where worn tubes would be prefered over new tubes under given circumstances. Even a cheap tube over some hi-dollar/hi quality piece for that matter.

    The reason I decided to check out a tube amp to begin with was to have one amp that could easily be altered so it didn't sound like the same amp and I'm not dissappointed in the results so far.
     
  20. specplyrz

    specplyrz Banned

    Nov 11, 2005
    Mohawk,

    This argument could go on for years. It has been hasshed around on other sites, and basicly it goes nowhere.

    I have seen an engineer post, that if the amp is used ALOT, 18- 24 month replacement in not unreasonable.

    So, there you have it. When I am using a 1600.00 bass head (svt) I am not going to chance damaging my output section with "tubes last 20 years retoric". There is too much information from countless resources on the web, from my amplifier manuals to gamble with the amp.

    Bottom line, when I hear a difference in tone from my amp, I'm changing the tubes.

    There are cars with 500,000 miles on them, still running strong, never been rebuilt...but out of the countless tens of millions, their percentage is nil.

    Like I said, there is ALWAYS an exception to every rule.
     



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