Heathkit SB-1000 Ni-Chr PARASITIC SUPPRESSOR

Discussion in 'Amateur Radio Amplifiers' started by N9ALE, Sep 5, 2019.

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  1. N9ALE

    N9ALE XML Subscriber QRZ Page

    I have seen these on eBay and am wondering if they are any good. I found one reference that said they might cause problems(no explanation given).
    Just wondering if anyone had any experience with them.
    Jon
    N9ALE
     
  2. N8CBX

    N8CBX Ham Member QRZ Page

    What is wrong with the original suppressors? Oh, these must be the hair-pin ones? Don't waist your money.
    Jan N8CBX
     
  3. N9ALE

    N9ALE XML Subscriber QRZ Page

    Jan,
    Nothing is wrong with that I know of, I am replacing some caps and the plate choke and thought if these offer some benefit I would stick one in...
    Thanks for the quick reply
    Jon N9ALE
     
  4. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    The best bet is to make them up exactly like the ones you have... resistor size, type, wire gauge and turns count. Several amp repair vets here use OY resistors instead of the hard to find or expensive carbon comps.

    Carbon comp resistors in the old ones go high in value from heat, but the only way to verify this is to clip the inductor. If the other parts in the plate side of your amp have suffered heat damage, stack the odds in your favor by making up new suppressors and replace them while you're in there.
     
  5. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Thousands of Heathkit amps have operated just fine for over 50 years as designed. Don't fall for magic beans, errr wire.
     
    WQ4G, K2XT and KD2ACO like this.
  6. N9ALE

    N9ALE XML Subscriber QRZ Page

    Oh darn, I traded the cow for that magic wire;). Thanks Chris I will order up a resistor or two and make one up.
    I am missing my amp:(
     
  7. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Sure! I've rebuilt several Heath amps and always make up new suppressors, clip the wire on the old ones, and measure the old resistor out of morbid curiosity. The values on the 40+ year old CC resistors are usually way high. If the price of new CC Rs makes you gag, try these instead.

    https://www.digikey.com/product-detail/en/ohmite/OY470KE/OY470KE-ND/823986

    Many new "carbon comp" resistors are not made like the old ones and are actually 'spiral wound' inside, i.e. higher inductance than the old units you are replacing.

    NOS carbon comps may not be much better than the ones you are replacing due to bad storage conditions over the decades, hence my personal preference is to use new Ohmite OY series units after lots of back and fourth discussing this topic with several regular posters here.

    There have been a lot of threads in this forum on this subject.

    This interesting tidbit is from W8JI's website.

    [​IMG]

    https://www.w8ji.com/vhf_stability.htm
     
    Last edited: Sep 6, 2019
    N2AMM likes this.
  8. N9ALE

    N9ALE XML Subscriber QRZ Page

    Chris,
    I had actually hit w8ji's website earlier but I was tired and my old brain just was not absorbing a lot.
    Thanks for the tips I will get on digikeys site tomorrow and order up some 100 ohm resistors and
    make me a suppressor.
     
  9. N8FVJ

    N8FVJ Ham Member QRZ Page

    I read the Rich Measures hairpin suppressors are poorer performing vs original wire turns over a 2 watt carbon resistor.
     
  10. W1QJ

    W1QJ Ham Member QRZ Page

    I'm not so sure those Nichorme "hair pin" suppressors were by Rick, AG6K. All of his suppressor stuff I have seen were coils and resistors. Over the years I saw several different varieties. Most I saw had cooked resistors that seemed to get so hot that the writing on the resistors burned off. Even Rick knew they were lousy on 10 meters. All units that came through this shop had them stripped out for a simple "original type" suppressor which is very effective when the resistor value is in the correct range. No magic required.
     

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