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Touching your tube is bad. Right?

Discussion in 'Amps and Cabs [BG]' started by SolarMan, Jan 27, 2013.

  1. I had a bit of a debate with a guitar buddy.

    I told him that after you change or touch a tube, you should wipe it clean with isopropyl alcohol.

    He fiddles with his tubes constantly, and he says he has never had a problem. Changing them in and out and buying "vintage" tubes that sound the same to me.

    The advice I was given in 1978 has stuck with me: "If you get oil from your skin on the tube, it can create a 'hot spot' that can affect performance or even destroy the tube"

    Is this true?
  2. Floyd Eye

    Floyd Eye Banned

    Feb 21, 2010
    St. Louis
    Never heard that one. Then again, I notice very clear differences between NOS tubes, which is why I have a bunch of them and roll them around according to my specific needs at the moment.
  3. Zembawy


    Mar 17, 2011
    Egypt, Cairo
    It IS true. In most cases, the oil coming from your skin on the tube will overheat and do damages to your tube.
  4. I don't think the glass enclosure gets hot enough for there to be any damage caused by the oil on your fingertips (I can't see a few microns of oil giving a massive insulating effect), though I have heard the same advice for halogen light bulbs, that the uneven heating can cause the glass to crack.
  5. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Eh, if you can avoid it, OK, but don't lose sleep over it.
  6. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    Phillipsburg, NJ
    I've always heard the same rumor and just always avoided skin to tube contact. Napkins are cheap so why tempt fate.
  7. The no touching rule applies to halogen bulbs and also some high power car headlight bulbs. In the case of audio tubes they just don't get hot enough for the oils to damage anything.
  8. f.c.geil


    May 12, 2011
    It is absolutely true. It isn't always immediate (although it sometimes is), but you will drastically shorten the life of the tube.
  9. dincz


    Sep 25, 2010
    Czech Republic
    I maintained low and high power tube equipment for decades and touching them was never considered to be (nor ever turned out to be) a problem.

    "Touching your tube is bad" sounds more like Victorian morality.
  10. Dredmahawkus


    Nov 4, 2012
    I fix cars and that rule does apply to headlights!
  11. Hi.

    Actually, the Halogen bulbs don't explode afterwards if You touch 'em with Your bare fingers, but the oily residue that's left there and get burned to the surface will affect the amount of light that passes through the glass.

    I've tried that in the past, confirmed it's true, and always avoid touching the bulb.

    If You read in the light of the tubes in Your amp, it could well be a problem, otherwise IME no.

  12. Touching your tube is bad. Right?
    That's what the Bible says.
  13. JonnyAngle

    JonnyAngle Dropping Acid Pedal Etching .com Supporting Member Commercial User

    Nov 24, 2008
    Maple Grove, MN
    This is the answer
  14. spacebassed


    Jan 31, 2009
    I always heard it will make you go blind. :eek:
  15. f.c.geil


    May 12, 2011
    Me, too, but it never did. So now, I treat it like I do any other private function... I just shut the door so nobody sees me. :bag:
  16. spacebassed


    Jan 31, 2009
    No need to make them go blind as well. :D
  17. That is what I was always told....to avoid touching them because oil from skin can bake. Same goes for photo bulbs.
  18. Staredge


    Aug 7, 2010
    Germantown, MD
    or wish they were.
  19. JFOC


    Oct 23, 2010
    new hampShire
    Better to touch the glass than the Pins. Pins are actually conducting power, not radiating heat.

    From Justin Holtons site
    " "I heard you should not touch your tubes at all (even when they're cool)."

    My dad even told me this one! I've read that the oil from your hands will build up on the tube causing it to run hotter than it should. Yeah, right. 1. In combo amps most of the heat goes up into the base of the tube, rather than out the side of the glass. 2. A minute bit of oil from your hand is NOT going to affect the tube's reliability/performance. Manufacturers print their logo on them don't they? Does that cause heat dissipation problems? Come on, I think cramming the tube up inside a metal chassis has more affect on heat dissipation than your fingerprint. Please, do not worry yourself over something as silly as this. You should, on the other hand, refrain from touching the tube's pins a lot. If you do accidently touch the pins there's a 99.99% chance that nothing will happen, but if you're having some weird problems cleaning the pins will sometimes solve them. Occasionally, after moving your amp to a gig or practice, you should make sure the tubes haven't shaken loose. Just give them a little push upwards from the bottom with, you guessed it, your hand."

  20. Mr. Foxen

    Mr. Foxen Commercial User

    Jul 24, 2009
    Bristol, UK
    Amp tinkerer at Ampstack
    Dirty tubes smell funny when they get hot. That's about it. They are made of glass, glass is famously inert, which is why you can store chemicals in them without them dissolving, and food in them without it tasting of glass. As for carbon deposits upsetting them, those fancy hifi tubes that are black inside? Guess what the black is.