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First pedal kit build troubleshooting

Discussion in 'Burnt Fingers DIY Effects' started by Seasicksailor, Nov 17, 2020.

  1. Seasicksailor

    Seasicksailor Friend of Leo's

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    Hello lovely people!

    I just build my first (functioning) kit pedal, and I am over the moon. I can see how it can be addictive despite the frustrations involved (or perhaps because of them?).

    However, I am having an issue with a weird noise I haven't come across in a pedal before. It's an EP Booster type. It works 'just fine' (and sounds amazing), but when it's on it's making a low, warbly humming noise which stays constant regardless of the level of boost. It actually took me a while to notice.

    My intention is to start over with re-soldering etc... but I thought I'd ask here assuming the noise is more familiar to you and you could perhaps point me to the most likely suspect.

    See video for noise:


    THANK YOU!!

    PS There seems to be a slight grounding issue as well. There is a slight hiss which goes when I touch the pedal (I'll re-check the grounding connections). But the video noise I am talking about is qualitatively different.
     
    Digital Larry likes this.
  2. Urshurak776

    Urshurak776 Tele-Holic

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    Sounds like a ground issue, definitely. Make sure the jacks are touching metal on the inside of the enclosure. I have had some where you need to scrape a little bit to ensure they touch metal. The case may have some paint there.
     
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  3. Seasicksailor

    Seasicksailor Friend of Leo's

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    THANK YOU! I'll try that!
     
  4. MojoTrwall

    MojoTrwall Tele-Meister

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    First build are often not clean regarding wiring.

    I'd check that everything is grounded and watch for wire.

    I don't hear much noise on the video, a regulated power supply really helps tho.

    Best advice for beginner too : look for pcb mount pots.
     
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  5. Seasicksailor

    Seasicksailor Friend of Leo's

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    Thanks! I'll double check the jack wiring, especial the grounds. Yep, the pot is pcb mounted... one thing less to worry about. :)
     
  6. Seasicksailor

    Seasicksailor Friend of Leo's

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    Ok... still at a frustrating loss. I reflowed connections... scraped where the jacks contact the enclosure... that noise is still there. I took everything out of the enclosure and tried it again... noise still there.

    I attach some photos... if anyone can spot anything particularly suspicious I'd be eternally grateful! I know the link to the switch from the main PCB looks a bit dodgy. Unless you come up with something else, my plan is to remove and replace that cable. But that's going to be really tough and likely to end up in a worse mess. :(

    01.jpg 02.jpg 03.jpg 04.jpg 05.jpg 06.jpg 07.jpg
     
  7. Seasicksailor

    Seasicksailor Friend of Leo's

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    Ok... this is embarrassing... the warble WAS the power supply. :oops: I just powered it through my pedalboard and it's gone. However, it's still hissy. I wonder whether I have missed any ground connections? I don't think so though.
     
    Digital Larry likes this.
  8. Seasicksailor

    Seasicksailor Friend of Leo's

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    By the way, the 'problematic' power supply should have been ok in terms of specs and it works fine with other stuff.
     
  9. Seasicksailor

    Seasicksailor Friend of Leo's

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    IT'S WORKING!!!!

    I reconnected all the wires to the jacks and replaced one that looked a bit burnt, and I connected the grounds of the jacks directly to each other. One of those things did it!!

    Thank you all!!!
     
  10. jrblue

    jrblue Friend of Leo's

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    Another post that says that something works perfectly. Except it doesn't. I've buit and serviced many pedals, all DIY or kit, often modded, and it is awfully easy to make mistakes that you can't readily catch yourself because, of course, your mind naturally thinks it's right. What I do now is to double check everything as I go, literally reading the instructions out loud, checking pics and schematic, and if possible checking continuity. This cuts down errors hugely by catching them early. But I still encounter trouble at times. The main sources are, in order of likelihood: missing ground connection (especially a build relying on a mechanical ground through the housing); fault (short, loss of continuity, etc.) caused when stuffing circuit into box; bad or broken solder point; assembly error. Since I haver limited electronics circuit-design knowledge, I really rely most of all on getting the instructions right from the get-go, as troubleshooting becomes shot-in-the-dark work. Try a battery, jury-rigged if necessary, to eliminate power supply issues. Try the unit outside of your regular signal chain and board. Particularly with a boost, you may be hearing amplified noise with a source outside the pedal...other pedals, room lights, etc.
     
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  11. Seasicksailor

    Seasicksailor Friend of Leo's

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    Good suggestions there!
     
  12. Digital Larry

    Digital Larry Friend of Leo's Gold Supporter

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    Circuits have a concept called PSRR - power supply rejection ratio. Many AC adapters aren't putting out flat DC - there's some 60 or 120 cycle riding on it (or 50/100). Some circuits will further regulate that inside to create a better DC. Most circuits at least have a series resistor on the power input, maybe 100 ohms, going into an electrolytic cap, e.g. 10 - 100 uF, which does filter a bit more.

    "Hiss" is usually not power supply related. You built a high gain circuit? Welcome to hissville. There are ways to reduce hiss but it's not usually a matter of checking your soldering.

    One of my favorite aspects of my modeler is that even with super high gain it is very quiet, and there's a very effective noise gate on top of that.
     
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  13. Seasicksailor

    Seasicksailor Friend of Leo's

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    Thanks Larry! Great info.
     
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