“CW Scrubber” kit is now “CW Regen Filter” kit

The Xtal Set Society offers a number of kits, aimed mostly at those wanting to experiment with shortwave reception using crystal and simple 1-transistor receivers. Also in the mix are a few pieces of simple test equipment like attenuators and dummy loads.

Their ad in CQ Magazine caught my eye some time ago and I finally got around to checking it out.

The ad mentions the CW Scrubber Kit that “scrubs away galactic noise”, resulting in clearer CW tones in the headphones. On their website the kit is called a CW Regen Filter (scroll a bit over halfway down) and costs $50 without a case ($70 with case).

My initial impression is that it’s way over-priced for what it is.

I can’t find any reviews online and I wonder if any are in the works – I’d love to read one that would change my mind.



  8 comments for ““CW Scrubber” kit is now “CW Regen Filter” kit

  1. Dennis Burton
    December 1, 2012 at 11:13 am

    John , Dennis Burton, N5DRB here, I just recently had a QRP contact with With Woody Hester WD9F . He was using the “Scrubber” designed by Phil Anderson, K0XI. It is featured in the Nov. CQ mag. I was operating a recently built AC-1 Junior one tube rig which put out about 750 MW . Woody said that he found my sig using the scrubber and that when he turned it off I would drop below the noise floor and he could not hear me at all. He said it was a very conclusive test for him to see what the scrubber would do . You might check with him to see if the scrubber you mentioned above are one and the same. I got an itch to build it myself.

    Dennis, N5DRB

    • December 1, 2012 at 11:33 am

      Thanks for the reply, Dennis…I’ll drop him an email.

      • December 1, 2012 at 1:28 pm

        Via email from Woody WD9P, posted with permission:

        Hi John. Great to hear from you. Yes. I completed the “Scrubber” kit last week and it’s performance is amazing. Simply put, the QSO I had with Dennis would not have happened without it. He was just below my noise floor with the “Scrubber” bypassed but kicking in the filter dropped the noise floor dramatically and then, with the Regen. Pot., I was able to tweak his signal up to what sounded like a solid 549 in my headset. Dennis and I had a fun solid copy QSO that would not have happened without the filter. He was running 750mw a little over 500 miles from my QTH and 40M was marginal at about 3pm.

        Circuit board and components are all great quality, all parts, including a very nice enclosure were provided and accounted for and the build instructions were straight forward. I don’t own an oscilloscope for alignment but I was able to use my VOM to perform all voltage and resisance checks and then I tweaked the three thumb pots while centered on a weak CW signal with my rigs filters out and no DSP in line just adjusting each for optimum performance. I’m sure an Engineer with an Oscilloscope (like K0XI) would be critical of this method of alignment but practically speaking, it sure worked well for me.

        I’m using my “Scrubber” with my FT-817ND and it’s made that rig a LOT more fun to operate. It dramatically drops the noise floor and that’s nice even for strong sigs .. then it’s ability to bring a weak signal up to Q5 copy in the headset is just spectacular.

        I haven’t had a chance to try it out in the QRP Fox hunts yet but I’m thinking my ability to bag pelts on the left coast will be greatly improved. I also think it will make it possible to copy very weak DX sigs I wouldn’t be able to otherwise.

        This could turn out to be the best $70 I’ve spent in my shack in a long time! Get one! You’ll love it! / Woody / WD9F

        • David J Wilcox K8WPE
          February 24, 2013 at 12:03 pm


          I just completed the scrubber and it does seem to work to reduce background noise and peak a weal signal but even after talking with Phil at the Xtal Set Society I cannot get any variation of the voltage when trying to “tune up” the scrubber. I get constant voltages with a Fluke high end digital VOM and an cheaper Chinese analog VOM. I can hear a difference when adjusting the thumb pots when listening to a weak CW signal but I only get a fixed voltage on my meter no matter where the thumb pot is set. I can’t “peak” the signal either. All the thumb pots work like a tone control, high frequencies CW and more base frequency response CCW. Do you have any idea where I should look. One friend told me to use a VTVM as even the Fluke VOM loads down the circuit too much. I don’t have a scope available.


          Dave K8WPE

  2. Dave AE6RQ
    December 31, 2012 at 12:29 am

    Hi John –

    Google found this for me. http://www.flickr.com/photos/gtppilot/sets/72157632153518261/

    It sound like fun and more knobs to twiddle.

    Now if I ever finish my binaural NE SCAF filter waiting on my shelf..

    • December 31, 2012 at 8:47 am

      Interesting Dave – tnx for passing that along. It’s been a while since I melted any solder here too…

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