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  1. Colin James Wonfor

    A DC Blocker to help stop transformer HUM

    What is the max forward voltage I see anti-reversal diodes but no over voltage protection on caps. Under peak in rush this could be high and on s/c loads it will be high. Also I would like to see a temp rating of 105C not 85C, also what is the max ripple current? Having just check his website I...
  2. Colin James Wonfor

    A DC Blocker to help stop transformer HUM

    It is not the gaps it the non conduction a backing EMF come from the transformer when current is switched of fast, it is the noise it put down the mains to other equipment that concerns me. OH you have to sign on to the SECA site.
  3. Colin James Wonfor

    A DC Blocker to help stop transformer HUM

    No it does not but because the current switch OFF quickly you get noise and harmonic. See the typical graph of noise.
  4. Colin James Wonfor

    A DC Blocker to help stop transformer HUM

    The above mention DC has a small problem I can well I can see two, but one is more important, the 1.4 approx voltage drop across the bridge will cause noise on the mains at zero to 1.4VAC This is the one I have used and it works well. And few numbers to look at. More info can be found here...
  5. Colin James Wonfor

    A DC Blocker to help stop transformer HUM

    Here is a PCB I did with SSR 2 channel power switch and filters plus a DC blocking circuit. Here is the BOM the PCB is available via https://seca.freeforums.net/thread/245/anybody-wanting-build-m100-kit
  6. Colin James Wonfor

    DIY: Mains Line/Noise/EMI Filtering

    Hi all, long time not been here I am doing a new power amp and I designed filter pcb with Low Noise SSR (my patent} if all goes well some of these PCB will be available.
  7. Colin James Wonfor

    EWA designs for sale

    Due to old age and not feeling good I will be winding up EWA electronics ASAP. I am also looking for a buyer to take on the designs for the future.
  8. Colin James Wonfor

    A bit about your host....

    Amir, I am sorry to say this is the first time I have looked at this page, and found it very interesting. Like you I had family member keen, well silly keen on electronics. My Granddad and Dad were mad scientists, Granddad taught me about Tubes/Valve and Dad semiconductors (Germanium). But...
  9. Colin James Wonfor

    Introductions anyone?

    Hi All, Sorry not been here for while but I wish you all a Happy Christmas .
  10. Colin James Wonfor

    Post a picture, a photograph, a drawing, a screenshot, ...no words.

    Loch Linnhe near Fort William Scotland. https://en.wikipedia.org/wiki/Loch_Linnhe
  11. Colin James Wonfor

    Introductions anyone?

    Hello were are you in the UK ?
  12. Colin James Wonfor

    Post a picture, a photograph, a drawing, a screenshot, ...no words.

    Please take some photo,s f Lynton and Lynmouth next your there I spent a happy childhood there with my GrandMa.
  13. Colin James Wonfor

    Whoops Sorry

    Removed
  14. Colin James Wonfor

    Magic Smoke!

    See if you let smoke escape unit dies, but if you encase the devices in a epoxy glue to keep the smoke in do they live longer or make a bigger bang???
  15. Colin James Wonfor

    Introductions anyone?

    Hello from London UK, wet here this morning.
  16. Colin James Wonfor

    A Fun MC to MM gain stage

    I Think I used 3K117 and 3J254 RF Fets, I have long since lost all the info. Also tried Fetlingtons but they were crap. Oh and a few tubes ECC88 I think. Magic numbers 7,10,12 in the Bible, and 42 for "Hitch-hikers Guide to the Galaxy" it was to see if there was any fans out there, oh found none.
  17. Colin James Wonfor

    A Fun MC to MM gain stage

    I have just noticed the Bible references in the text above the number 7, now let fine some with 42??
  18. Colin James Wonfor

    A Fun MC to MM gain stage

    That is good, I used in mine two tranny per channel and common the opposite Base to base and used a green led which seemed to reduce the noise, and standard 78/79 series regs and fed them in a low noise OP -amp as a shunt regulator. Yes the input impedance was fine and ideal for the old low Z MC...
  19. Colin James Wonfor

    A Fun MC to MM gain stage

    I first used it in the A.C.Magnum pre-amps in 1977 so it has been around for while, but now with matching complementary transistor on the same substrate, much better performances are possible.
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