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1N4148 diodes in COT Clone

Discussion in 'Burnt Fingers DIY Effects' started by funkysoul, Apr 9, 2020.

  1. funkysoul

    funkysoul Tele-Meister

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    so as a first time pedal build i broke in process my 2 AO1148 diodes.so i wait some new to come.'till then please tell me if i put on board some 1N4148 that i' ve got in hand what i can expect.thanks
     
  2. sirbergersworth

    sirbergersworth Tele-Holic

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    What pedal are you building?
     
  3. funkysoul

    funkysoul Tele-Meister

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  4. sirbergersworth

    sirbergersworth Tele-Holic

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    Should be fine. The character of the breakup will be somewhat different. You could try to find something with a similar forward voltage as the broken ones.
     
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  5. funkysoul

    funkysoul Tele-Meister

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    thanks
     
  6. voskarp

    voskarp Tele-Holic

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    I built mine with a switch so I can choose between 1N34A germanium- and 1N4148 silicone diodes.
     
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  7. voskarp

    voskarp Tele-Holic

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    The Fuzz Dog kit uses 1N270 germanium diodes.

    You got to be really careful with the soldering iron so the germanium diodes (OA1182 are germanium diodes) don't get too hot. Only a couple of seconds of contact, and use a heatsink (I use a hemostat), between where you solder the leads and the diode.
     
    Last edited: Apr 10, 2020
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  8. funkysoul

    funkysoul Tele-Meister

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    so i put the 1N4148 on board they are smaller at size but i dont know their value as i cant mesure them but i get nice sounds.its very warm pedal no harsh overdive at all makes my tele sounds so good.and boost my amp veeery nice.....i think when the right diodes germanium comes it will take the place of my beloved boss sd-1...we'll see
     

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    Last edited: Apr 10, 2020
  9. tah1962

    tah1962 Friend of Leo's

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    I recently built a BYOC 855 drive (Ibanez OD855 Overdrive II clone) that called for 1N34A germanium diodes. With two germanium diodes in the pedal, I couldn’t hit unity gain with the volume knob until I set it around the 3 o’clock position because of their lower forward voltage. I ended up replacing them with two 1N4148 silicone diodes. The pedal now sounds much more balanced and the overdrive sound is much more pleasant to my ears. I wasn’t a fan of the germanium diodes. YMMV.

    FA7386A2-81C1-4E34-BBEC-D0B2D530EBBB.jpeg
     
  10. funkysoul

    funkysoul Tele-Meister

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    i have read the same info about germanium volume loss but i have to do it to see what will be....or i think so
     
  11. funkysoul

    funkysoul Tele-Meister

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    well i'm just curious.....what if i place the 2 AO1148 ger diodes in Series and hold the 1 silicon? should i get more brake up and hold some volume still?
     
  12. voskarp

    voskarp Tele-Holic

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    You could do that, and create some asymmetric clipping which I think is good. (For more asymmetry use only one OA1182 with one 1N4148)

    The germanium diode OA1182 gives more clipping which means more distortion and less volume than the silicone 1N4148. If you put two in series you'll get higher forward voltage which means less clipping.
     
    Last edited: Apr 11, 2020
  13. funkysoul

    funkysoul Tele-Meister

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    i'll do and i'll report back
     
  14. voskarp

    voskarp Tele-Holic

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    You could do as I did in my COT-clone; I put the extra diode in series on a switch so I could choose between symmetric and asymmetric clipping.
     
  15. funkysoul

    funkysoul Tele-Meister

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    so there is something that buggs me.i realy dont know if i have put the right capacitors in the right place...so if you look the photo that i post before there are 2 green of them 1 bigger and one smaller.the
    diagram https://www.musikding.de/docs/musikding/chapel/chapeloftone_schalt.pdf has them in the C2 and CE3 written with their values so i can see them.but the capacitors doesnt really has uppon them the same values.i mean that the big one writes A2 124J and the small nothing at all so i place them radom.and now it buggs me a bit to change them and see the diference....what you think

    yes it would nice but 1rst i dont know how to do it and 2nd theres no space at all in there
     
  16. voskarp

    voskarp Tele-Holic

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    Looks like you put them right.

    124J= 120000 (12 with 4 zeroes) pF, J is just the tolerance +-5%.

    120000pF is 120nF.

    The small one should read 563(J).
     
    Last edited: Apr 12, 2020
  17. funkysoul

    funkysoul Tele-Meister

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    well thats.
     
  18. voskarp

    voskarp Tele-Holic

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    As a note: the Schottky diode BAT46 can be a good replacement for this circuit. It has a forward voltage closer to the germanium diodes than the 1n4148.
     
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  19. funkysoul

    funkysoul Tele-Meister

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    i dont have now one.the others tha i've got are FR107 and 1N4007

    over all i found a bit darker than i'd like.is that gonna change with the germaniums or any other diode or i have to change anything else?
     
  20. voskarp

    voskarp Tele-Holic

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    Those diodes may not be the most suitable.

    Can't you change the tone with the "Nature"- knob? It should go quite bright and cut most of the low end.
     
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