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.

Friday, January 23, 2015

Simple FET Blender

Here's a simple blending circuit that uses a JFET to allow you to blend between effected signal and clean signal. I've used this on Big Muffs before and it's quite useful.


31 comments:

  1. I tried to use this with my populated Blower Box and I am getting phasing issues at 50% blend. The volume of the clean and effected are dropped to almost nothing. I used a J201. I am wondering if a split and blend would work better. thoughts?

    Cody

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  2. Never had phasing issues with it on the 2 pedals I've added this to. Wonder if there's something with the RAT-based circuit that just doesn't play nice with with this one. This is a rather simple blender, so a more complex one (maybe the Run Off Groove Splitter-Blend?) with buffers and whatnot might be better suited for the Blower Box.

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    1. Thanks, I will play with it some more tonight. I populated a split and blend to give it a try also.

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  3. Verified, just made up 2 of these for Big Muffs and they work great! Thanks!

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  4. If I want to make one of them - blend and affected pedal - always on, which one would be better bro?

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    1. Not quite sure what you're asking... Do you want to make a pedal that has this instead of a footswitch?

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    2. I don't see why not. Though you might want to try the Split n Blend. This one can cause some unwanted phasing. Just depends on the circuit you're trying to blend I guess.

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    3. just want to add this to my big muff

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  5. Can I use 2SK30A instead? I knowthat has different pinout.

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  6. how to mix this with bear hug fet comp?

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  7. this works really well.
    i modded it after my true bypass switch so i can have clean sound.
    it works well but there is a large noise when i press bypass. i thought maybe a capacitor on the bypass will solve it.
    any thoughts?

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    Replies
    1. You may need to add a pulldown resistor between input and ground. Start with 1M value.

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  8. Hello, I did it. it works. I have a question. When I set the potentiometer to 0, the clean signal is much quieter than if the potentiometer is twisted by 100%. Should it be or did I do something wrong?

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    1. What effect did you add it to?

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    2. I used it as a separate pedal for mixing pure signal and fuzz

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    3. Generally the fuzz is going to have a much higher volume than your clean tone. To get things to unity, turn the volume of the fuzz down.

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  9. Shit! I just finished a few minutes ago and it's perfect! It works perfect with a DOD FX25, thanks!!!
    Ps: I made it with a J112

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  10. Hey, I built the effect as a standalone pedal and it works fine... except, with some pedals (Big muff) it has a huge drop in the highs when I engage the pedal in the loop and no matter the potentiometer setting. It happens even with the potentiometer on full clean.
    Any idea what could be causing that?
    Thanks a lot for the layout btw! :)

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  11. Hi, I want to add a blender knob to an orange squeezer circuit, how can I wire it? Thank you!

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    1. Wire the send pad from the blender board to the in of whatever effect you want to add it to, then the out of the effect to the return pad. Wire the in/out pads of the blender board to the footswitch as normal.

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  12. hello. could you tell me the difference between the Fet Blender and the Split 'n Blend? i would use it to mix my old Tape delay (only the wet signal) to my true Bypass guitar signal.

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    1. The two circuits basically do the same thing, with both adding a buffer in parallel to the circuit you're adding it to. The Split 'n Blend just does it a little better, buffering the signal before it's split. You may run into some phase issues depending on the circuit you're adding it to, so research that before you commit any parts to solder.

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  13. I use this stupidly simple little genius to blend bass pickups after tone controls. Much better than passive blend. The pickups don't load each other, giving their true sound. Then the output goes to a bass booster, volume pot, then out to the wild for the rest of the shaping.

    It's funny that after building many circuits, this is the most useful one, yet the simplest to build by far. :D

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    1. A note: don't do this on single coil pickups because they depend on each other to cancel hum. For example, won't work nicely on classic Jazz Bass pickups.
      I did it on a bass with dual rail pickups (still in single coil enclosure) already hum-bucking on their own.

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  14. Is the 10UF cap polarized? and if so which way is the polarity?

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    1. Thought I hit reply rather than comment... See my response just below.

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  15. It is polarized. It's a little hard to see, but in the diagram there's a white stripe on the right side that indicates the negative side (attached to lug 1 of the pot).

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  16. Hi.
    I'm having a problem when I put the Muff with the gain on maximum and high volume. It creates feedback, even putting the entire blend pot to the effect. Has anyone had this problem? any suggestion? Thanks

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