In what device would I find a 1 M-ohm resistor? (Rip project)

Discussion in 'General Electronics Chat' started by Jacob J, Dec 30, 2010.

  1. Jacob J

    Thread Starter Active Member

    Jun 18, 2009
    159
    0
    Hey all

    I have now tried to rip various old hardware I had on hand for components. But I need some 1 mega ohm resistors and I havnt been able to find some in PSU's, PCI cards or anything other, that has with computers to do.

    What other devices could contain such a 1 M ohm resistor?
     
  2. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Why don't you buy an assortment of resistor values?

    "In the good old days" I ordered any resistor values I wanted in any quantity. Then they got less expensive so they were sold in quantities of 10.

    Then when I needed some 1/4W resistors I bought a Velleman assortment that was on sale at a local store.
     
  3. #12

    Expert

    Nov 30, 2010
    16,250
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    Find something with vacuum tubes in it and look for meg ohm resistors in there.
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,764
    2,534
    What part of the world are you. You'll note the old hands have their location on their profiles, and get displayed with their posts. This allows other folks to recommend parts sources.

    For example, you can buy a 5 pack ¼W 1MΩ for 99¢ from Radio Shack.

    http://www.radioshack.com/product/index.jsp?productId=2062351
     
  5. Audioguru

    New Member

    Dec 20, 2007
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    This is the year 2010 and is nearly 2011.
    Vacuum tubes were used 50 years and more ago.
    Good luck trying to find one today.

    In those days the resistors were carbon-composition and they changed their value with time like a clock.
     
  6. #12

    Expert

    Nov 30, 2010
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    You're right. Any carbon resistor, 100k and up, walked right off the high end of their tolerance in very few years, but what kind of quality can one expect for less than 99 cents?

    ps, Vacuum tube guitar amplifiers are still being mass manufactured today.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    I have seen solid state amplifiers with two vacuum tubes glowing on top. The vacuum tubes were for show and were not used in the amplifier circuit.

    I guess you know that a vacuum tube fails soon. Some rock bands replace theirs before each show.
     
  8. #12

    Expert

    Nov 30, 2010
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    Yes. After 35 years working with bands and vacuum tube amplifiers, I know the tubes have built in failure mechanisms. I also know how to find out which amplifiers actually use vacuum tubes.
     
  9. Audioguru

    New Member

    Dec 20, 2007
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    Yes, they are the ones with no deep bass, no high audio frequencies, lots of distortion and a BAAAD sound.
     
  10. #12

    Expert

    Nov 30, 2010
    16,250
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    I just love when you go off on a rant.
     
  11. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    Beg to differ if you bought the good stuff like some of the Macintosh line. Some people prefer the sound of a good tube amp but most of it is just being able to brag about your space heater. To this day they're still built and sold but there aren't many tube suppliers anymore asides from Russia who's kept a lot of it alive.

    If you ever happen on an old tube amp, preamp or receiver even if it doesn't work you can often make a fortune selling the 12AX7 and other tubes out of them if they're one of the sought after varieties. I was given an old receiver that needed serious work, did some research on the tubes and ended up selling some of the Mullard and RCA tubes in it for $100 apiece on eBay.
     
  12. TheLaw

    Member

    Sep 2, 2010
    228
    2
    I bought a component grab bag off Jameco. It was $50 and came with a total of about 1,000 components. I thought it would be a good deal, but it wound up being a total ripoff. (Atleast from Jameco).

    The capacitor part of the grab bag was supposed to have 100 assorted electrolytic caps. I got *37* 470uF 35V axial (who the hell uses axial?) capacitors from a company called Jackcon. Out of the entire bunch, I only got one Nichicon and two Nippon Chemi-Cons...

    I was so furious.

    So moral of the story...

    Make sure you know what you are getting in the assortment. I'd reccomend just spending the extra couple of bucks and going on Mouser/Digikey to get standard value resistors and of good quality (metal oxide perhaps).

    Maybe not. My personal experience.
     
  13. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
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    I only buy those surprise boxes from http://www.goldmine-elec.com and have never been disappointed.

    Item :G2200
    Item :G9321
    Item :G17225
     
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