When to change tubes?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by SlyStrat, Jan 20, 2006.

  1. SlyStrat

    SlyStrat Supporting Member

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    What happens to the amps tone if the tubes are old or played a lot? How do I know when to change tubes?
     
  2. VaughnC

    VaughnC Supporting Member

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    If you like what you're hearing, I wouldn't worry about it unless one dies or gets noisy or microphonic. Typically, an amp will start to sound mushy or lack power with weak tubes....but that could be a good thing for some players. A few years ago, I was in a band with a guy who used an old Ampeg head and the tubes were rusted to their sockets....and that amp sounded pretty good to me. God help him though if he needed to replace a tube at a gig!!
     
  3. John Phillips

    John Phillips Member

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    The really sad thing is when someone reads that "you need to change tubes every year or so", so without any other reference they take out the perfectly-working old-stock tubes in their vintage amp, throw them away, and fit new-production ones.

    I've seen this so many times... usually when the amp then comes to me for repair because the crappy new tubes have died almost immediately (which is the only thing wrong with it) and the owner says "but they're new tubes" and I ask what happened to the old ones... :(

    Of course, if your amp has new-production tubes in they will probably need replacing every couple of years :rolleyes:. Old-stock tubes will typically last five to ten times as long as Old Tele man said, or even more - decades in an amp that isn't being gigged hard regularly - even the power tubes. I've worked on many amps from the 70s and even the 60s with their original preamp tubes in, working perfectly, and even a few with original power tubes from the 70s and early 80s. You don't need to change them unless they're starting to show a fall-off in performance or have become noisy - hum, rattles or microphonics. If you're not sure, you can always get a set of new tubes (it's worth having a spare set for any amp anyway) and replace them - power tubes first - and see if it makes a noticeable difference. Keep the old ones as spares... or the new ones, if they don't sound any better.
     
  4. kdixon1029

    kdixon1029 Member

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    JP,
    I know what you mean my mesa tremoverb combo (1993) had the original preamp and power tubes until last year and I was giging a lot at least 5 times a month. I only changed because I had a speaker go bad and the tech suggested that I do a complete replacement. I wish I had been on this board back then!
     
  5. SlyStrat

    SlyStrat Supporting Member

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    Well, I bought a used Marshall combo that was made in '99. The tubes look new, but when I took the back covers off, they kinda were stuck on, leading me to think the tubes were never changed. The amp sounds kinda thin to me. No other weird noises.
     

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