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Dallas Rangemaster resistors

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  • Dallas Rangemaster resistors

    Hi,

    I'm specing out the component list for a Rangemaster clone I intend to build. My first question concerns resistors. Original schematics call for three: 470K, 68K, 3.9K - and articles I've read indicate a 1/4W power rating for all three. I'm planning (at the moment) to order most components from Mojotone, and they only stock carbon comp or metal film resistors with 1/2W power rating and over. My newbee common sense tells me that EXCEEDING the recommended power rating should NOT be a problem, right?

    What TYPE of resistors BTW were in the original Rangemaster? Carbon comp? Metal film? Can anyone validate an article I've read stating that metal film resistors would significantly reduce noise in a Rangemaster?

    thanx!

  • #2
    Looking at this pic, they look to be old carbon comp resistors...probably 1/2 watt or greater.
    With those values and 9 volts, you would be fine at 1/4 watt.

    And your common sense is working fine.

    Metal film = less noise?
    Maybe yes, maybe no.
    There are times when carbon comps have a lot of noise that shows up as "static"-like chatter.
    But metal films can have issues with more inductance and acting a bit more like a radio antenna.
    ...and rangemasters are prone to picking up broadcasts anyway,

    I'd start with the ol' carbon comps, then switch to metal films if you are so inclined.


    GutShot pic of a Rangemaster (not mine).
    http://www.geofex.com/Article_Folder...aster/DRM2.jpg
    Blind Doc Jones' Pickles....Cures What Ails Ya

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    • #3
      btw, have you read Jack's writeup on the Rangemaster?
      The man is full of good insights.

      http://www.geofex.com/Article_Folder...er/atboost.pdf
      Blind Doc Jones' Pickles....Cures What Ails Ya

      Comment


      • #4
        Originally posted by blindopher View Post
        Hi,

        I'm specing out the component list for a Rangemaster clone I intend to build. My first question concerns resistors. Original schematics call for three: 470K, 68K, 3.9K - and articles I've read indicate a 1/4W power rating for all three. I'm planning (at the moment) to order most components from Mojotone, and they only stock carbon comp or metal film resistors with 1/2W power rating and over. My newbee common sense tells me that EXCEEDING the recommended power rating should NOT be a problem, right?

        What TYPE of resistors BTW were in the original Rangemaster? Carbon comp? Metal film? Can anyone validate an article I've read stating that metal film resistors would significantly reduce noise in a Rangemaster?

        thanx!
        It's a non-issue - the 1/2W resistors will be just fine.

        I'd recommend the metal film resistors if you want the best performance / low noise... if you want to be vintage-correct, go with carbon comp. Yes, there is definitely a difference in noise... some folks think carbon comp brings teh mojo, but I don't think it makes a big difference. It does make a difference in terms of noise levels though, so if that's important to you, I'd definitely go with metal film resistors.
        **********

        "Look at it this way: think of how stupid the average person is, and then realize half of 'em are stupider than that."

        - George Carlin

        "It shouldn't be expected that people are necessarily doing what they appear to be doing on records."

        - Sir George Martin, All You Need Is Ears

        "The music business will be revitalized by musicians, not the labels or Live Nation. When the musicians decide to put music first, instead of money, the public will flock to the fruits and the scene will be healthy again."

        - Bob Lefsetz, The Lefsetz Letter

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        • #5
          Originally posted by lefort_1 View Post
          Metal film = less noise?
          Maybe yes, maybe no.
          There are times when carbon comps have a lot of noise that shows up as "static"-like chatter.
          But metal films can have issues with more inductance and acting a bit more like a radio antenna.
          Watch the grounding and keep it in a good, all-metal case, and I don't think RFI should be a big issue, even with metal film resistors. You're absolutely right about their respective issues though...
          **********

          "Look at it this way: think of how stupid the average person is, and then realize half of 'em are stupider than that."

          - George Carlin

          "It shouldn't be expected that people are necessarily doing what they appear to be doing on records."

          - Sir George Martin, All You Need Is Ears

          "The music business will be revitalized by musicians, not the labels or Live Nation. When the musicians decide to put music first, instead of money, the public will flock to the fruits and the scene will be healthy again."

          - Bob Lefsetz, The Lefsetz Letter

          Comment


          • #6
            thanx to all!

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