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Saturday, November 22, 2014

JFET Boost

Here's a quicky. It's an old Dragonfly design and was my first perf build.



22 comments:

  1. Yes clean booster ,very very perfect

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  2. I built this pedal with mpf102 and it sounds ugly, is it possible that the replacement you use is not the right one?
    The transfer image lacks a hole for a resistance of 2.2k?

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  3. Replies
    1. Try 2N5457, or F245A. I used both, and works great.

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  4. https://www.youtube.com/edit?o=U&video_id=EITs60ZwEUI

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  5. Does this scheme work or do I need to change something in the leyout ?

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  6. To whom it may concern you can use a j113 if you change the 22k from 9v to a 10k just make sure to check pinout on transistor.

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  7. So, if you use a, say, 50k trimmer in place of the 22k bias resistor, you should be able to use other jfets and bias accordingly, right?

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  8. The pot is wired off board. The pads labeled "Boost 1" and "Boost 3" tell you which lugs to connect. Boost 2 is the circuit output, and the pot is a 100k audio/log taper. See the General Layout Notes tab for offboard wiring info.

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  9. For caps, use caps polar or non polar?

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  10. This comment has been removed by the author.

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  11. Still not work, i try with J201 and the same value of resistor an caps , but didnt work.

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  12. Does anyone know if this would work off 12v.building it into preamp section of a micro amp project. If not I can add another stepdown

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    Replies
    1. You might need to adjust the 22k resistor going from voltage to drain, but I would think it'd work fine on 12v

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  13. few questions:

    can i use this with a dynamic mic without distortion? or there's some kind of problem in impedance or smthing?

    can i replace this with a 2sk170bl? any ultra low noise replacement with the same pinouts as j201?

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  14. Permisi saya membuat ini dengan 2n5458 dengan potensio B100K suara terdengar kecil...
    Ada yang dapat membantu saya

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  15. Just completed this. My first attempt at using non strip perf board. I think i like it better. I get more of a sense of what is actually happening this way. It worked by the way. Although it sounds bad at low volume. Crackly. Im sure its my soldering though.

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