This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Tuesday, October 18, 2022

Boss SG-1 Slow Gear

 The Slow Gear emulates a guitarist riding the volume pot or a volume pedal, creating a swell effect. This will fit comfortably in a 1590B or 125B, though with the 1590B you'll probably want to wire the pots off board or use long-leg right angle pots mounted on the component side. Here's the schematic for reference.




12 comments:

  1. I have found reports that the 2sk30a can be subbed with a 2n5457 in this circuit. I

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    1. It might be. I forgot to add in the post that there's an extra pad for GSD pinout JFETS to the right of the package.

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    2. If one were to tweak elements of this circuit, where would you focus?

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  2. Thanks, looking forward to building this. According to the schematic the 3n3 capacitor should be 33n.

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  3. It Works. Sounds nice. I used a 33n cap and the 470nf cap I used was box film ( its electro on the map) I also put in 4 sockets for the Jfet and it works with 2n5457 in the extra space provided. Thanks for another fun project.

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  4. hello, thanks for another layout, could you do the layout for Ibanez Soundtank EM5.

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  5. The cap on the gate of Q2 should be 33n and not 3n3

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  6. I can call this confirmed & verified.

    Small modification I've made that, I've changed the 470nf cap to 10uf polarized for a longer attack duration. I've also connected a parallel spdt switch to that line and added another 10uf polarized cap, sending the caps negative to gnd directly, for a tad longer attack speed. This was suggested on Aion's Swell schematics by using 2 different caps (2.2uf and 10uf, and 470n was 680n), but i chose this as I wanted more of a reverse effect, and a longer, softer attack duration.

    Thanks for the layout!

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  7. Is it any way to add a LED responding to swelling effect?

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  8. Please, upload layout BOSS SP 1 spektrum, Digitech Hot Head distortion

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