Wednesday 9 March 2022

Electro Harmonix Bad Stone

 This is a monster!

It is based on the schematic by Lectric Fx which includes a recovery stage with internal trimpots to set the output volume.Schematic is avaiable HERE.




3 comments:

  1. Build it and it works. It needs a few corrections tho:
    1. Move 100k from m7 to p7
    2. Move 6k8 from 20c to 20d
    3. Move 100n from aa15 to ab15
    4. Move 470r from ag2 to ab2
    5. Move link from ab3 to ad3
    6. Move link from k-g9 to k-h9
    7. Reverse pin 1 and pin 3 of the rate pot
    Notes: Used 4009cn and sounded better than 4049ube in my build.
    Works as it should but signal is a bit distorted when at maximum. Have to play with the guitar knob to get the right level for non-distorted effect, however, it gets below the unity gain, meaning u need a booster to bring it back to normal level. Or alternatively, u can fix that by adjusting your picking style.
    U also need to select the op-amps carefully as the effect differs from one to another; settled for 4580 for ic3 and ic4 and 4558 for ic1 and ic2
    Note rate is not working in manual mode and this is normal; normal mode is mostly sensed at max of feedback pot.
    Cheers!

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    Replies
    1. This is amazing. Thanks for tackling this monster, spot the errors and for the advices on the ICs.
      Impressive.

      The layout is updated and TAGGED!.

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    2. Your work is amazing, 1264 layouts to date! I am glad to see all these solder enthusiasts helping and supporting your project. Cheers and keep it up!

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