Allen Bradley resistors?

Discussion in 'Shock Brother's DIY Amps' started by Uncle Daddy, May 11, 2019.

  1. Uncle Daddy

    Uncle Daddy Tele-Afflicted

    Sep 26, 2015
    Maldon, England
    Just came across this tip regarding AB resistors. Whaddya think?

    Allen Bradley RESISTORS special treatment method
    As stated Allen Bradley resistors are carbon composite, being made of an organic material they do have the tendency to absorb water from the atmosphere. This absorption can increase the actual resistance of the component, hence the slightly higher than normal tolerance published on this page. To fix this simply remove the water from the component and seal it. The best method is to place the resistor/s on a baking tray, set your oven to 80 degrees centigrade and leave in the oven for 8 hours. The secret is to remove the mositure slowly if you rush it it will become noisy in circuit. Once cooked seal the body of the component in Shellack (preferably the flakes) to stop any further water absorption. At the end of this procedure you will have a much lower noise, more closely tolerance resistors. Special thanks to Colin Cornish for this excellent tip.
  2. Blrfl

    Blrfl Tele-Holic

    May 3, 2018
    Northern Virginia
    I think that like most things from the Hi-Fi crowd, that should be taken with a boulder of salt.

    A good, calibrated sublimometer is a hard thing to find, especially one that can measure orangicity. There are two, maybe three in all of Europe. :rolleyes:

    In other words, they're that same kind of carbon resistors that have been manufactured by the billion for decades. Allen-Bradley made high-quality parts that were conservatively spec'd. They're no longer in that business because others have figured out how to do the same for less money.

    Also thank the author of the data sheet. A-B says to do this at 100°C and for a lot longer than eight hours.
    aerhed likes this.
  3. corliss1

    corliss1 Friend of Leo's Platinum Supporter

    Sep 13, 2008
    Lansing, MI
    Or you could just use modern resistors that don't have these issues?
    the fatch, DugT, Nickfl and 1 other person like this.
  4. Nickfl

    Nickfl Tele-Afflicted

    May 24, 2016
    Agreed. Either use carbon comps for what they are or use better parts off the shelf. Seems like a massive waste of effort to use carbon comp resistors for their alleged mojo and then spend hours baking that mojo right out of them.

    Unless you are a botiuque builder looking for some dubious BS to set yourself apart from everyone else's dubious marketing BS...
    the fatch, DugT and Uncle Daddy like this.
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