Extra noise

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  • #16820 Reply
    brach
    Moderator

    Mike…
    Sorry, i’ve been out of town. I just responded via email.
    -Brach

    #16828 Reply
    mike335
    Guest

    Brach,
    I tried my Mosky Power Station, it’s a less expensive device like the one spot. It has a 1.0 amp output power supply, and eight 9v, one 12v, and one 18v DC pedal power outputs. The noise is the same with the Mosky as far as I can tell. Would the 12v or 18v DC outputs possibly improve the noise issue? I have only tried the 9v outputs because I don’t know if it’s okay to use the higher voltage on the Quaverato. I’ll email you some photos of the Mosky.
    Mike

    #20425 Reply
    mike335
    Guest

    Brach,
    It’s been awhile, but I wanted to let you know that I finally got around to ordering and trying a 9V battery adapter with the Quaverato. It seems to work well, the noise is much diminished with the battery power. I haven’t tried the Quaverato¬†with other (wall-wart powered) effects in the chain yet, but hopefully this will resolve the obnoxious (to me) noise issues I was having when I used a power supply transformer with the Quaverato. I’m not sure if the circuit could be modified to permit quieter operation with power from a power supply, but the battery power seems to confirm that the noise is generated by the power supplies that I have and used to power the¬†Quaverato. Thanks for your help.
    Mike

    #22731 Reply
    Corry
    Guest

    Hey there, I’m posting to this thread because I’m experiencing an identical issue. Did the original poster end up figuring it out?
    When the depth knob is in the complete counter-clockwise position, there’s no issue. As soon as the depth knob is moved even slightly clockwise, there’s a high pitched drone that pulsates in accordance to the tremolo settings, and is present both when the pedal is activated or bypassed.
    For what it’s worth, this is a new issue that has arisen whilst trying to fix a different one. I was hearing a clicking noise every time the effect activated in the square wave setting. In attempt to fix this I carefully reflowed all the solder joints in the power/relay section and the micro-controller. That’s when the high-pitched drone started.

    #22745 Reply
    mike335
    Guest

    I’m not sure you’re experiencing the same symptoms as I was Corry. My Quaverato didn’t seem to produce different clicking noises in the square wave setting, although I rarely use this wave form. Using a battery with the appropriate adapter instead of a wall-wart transformer seemed to reduce the noise my pedal made. I also think it sounds better in the effects loop of my rig than it does inline to the guitar input with my rig.

    #22746 Reply
    brach
    Moderator

    Corry,
    That noise is still a misery to me. It is very interesting that it just started happening after you re-soldered the microcontroller pins. This gives me an idea…I know in other high frequency circuits that i’ve worked with this type of issue has been caused by flux (from the solder) on the board. At high frequencies flux can actually be inductive. So i’m wondering if something like that is happening here. The Quaverato is only operating a 16MHz, so that’s not too fast but it may be fast enough for whatever flux you are using to be inductive. Clean off all the flux on your PCB around the microcontroller and the crystal (and associated components). I make my own flux cleaner by mixing equal parts acetone (you can use fingernail polish remover) and rubbing alcohol. I use a q-tip to clean it off.
    This flux idea just came to me, so i have no idea if it’s related to the issue, but i hope so. The other times i’ve seen this issue, for some reason using linear power supplies has helped. Using a battery to test if the issue is power supply related is also helpful.
    I’m sorry for the trouble. Let me know if you have any luck after removing the flux.
    -Brach

    #25412 Reply
    cth515
    Participant

    I’ve had a similar/the same issue myself. Regardless of the power supply, I get the same noise described by others, which can be reduced using the depth control. I found that adding a decoupling capacitor to the ATmega328p fixed the issue. I soldered a 1uf 50V electrolytic across pins 7 and 8 (to the socket on the backside of the board, not to the IC itself!).

    I think that the microcontroller was dumping noise to the shared ground plane. I may be wrong, but this has fixed the issue for me. I’ll let Brach weigh in on this, as mine may be an older unit.

    #25413 Reply
    mike335
    Guest

    cth515, I’m wondering if you took any photos of your mod? I’m considering trying it myself, but I’m not sure how to identify pins 7 and 8 (Are they on the same side of the socket leg array where the legs project through the board, and which end do I count from? I don’t see any numbers printed on my board in the photos I took after I assembled my Quaverato). You must be more knowledgeable about electronics than the average stomp box builder (I just read and follow directions). Would this be an appropriate capacitor?:

    https://www.newark.com/nichicon/upw1h010mdd1td/aluminum-electrolytic-capacitor/dp/65R4084?CMP=KNC-GUSA-GEN-KWL-DSA-tCPATest47-NICHICON&mckv=s_dc%7Cpcrid%7C440527280623%7Cplid%7C%7Ckword%7C%7Cmatch%7Cb%7Cslid%7C%7Cproduct%7C%7Cpgrid%7C17246694501%7Cptaid%7Cdsa-96407174661%7C&gclid=Cj0KCQjw6ar4BRDnARIsAITGzlB4Lvm1MopkxGhnw6GedgtYymhfV5syEcaIMSBDt-aQMKPEuvqOnGgaAmxKEALw_wcB

    I guess we could exchange email addresses if you’re willing to share more guidance and information about your mod? Thanks, Mike.

    Email: mike335 at hawaiiantel dot net

    #25415 Reply
    brach
    Moderator

    Thank you for pitching in on this, cth515. It does make sense that decoupling the “noise making device” (the microcontroller) better would help cure the noise…although I’m pretty sure that I tired this with the noisy unit that i had and it didn’t help…but i was using a lower capacitance (around 220nf) so it makes sense that a much higher capacitance would make more of a difference. The board version shouldn’t make a difference of how well this works. The ground planes and power distribution path are very similar on both board versions. The ground planes are separated (digital and analog), but there are other ways for current to get through.
    I’m really glad that you found a solution that works for you! Good work!
    Mike353…yes, please go ahead and try this. The cap you linked to is much too large of a capacitance…use one of these:
    https://www.taydaelectronics.com/capacitors/electrolytic-capacitors/nichicon-1uf-50v-105c-radial-electrolytic-capacitor-5-11mm.html
    https://www.mouser.com/ProductDetail/KEMET/ESL105M100AC3AA?qs=HXFqYaX1Q2x0RWu%2FYCFzZA%3D%3D
    https://www.digikey.com/product-detail/en/rubycon/50YXJ1M5X11/1189-1421-ND/3134377
    Ideally you want a cap with a relatively low ESR (equivalent series resistance) which gives the noise a low impedance path to ground, but i’m not sure how practically important that is in this application.
    Here is a page with a graphic of the Atmega328p IC’s pinout:
    http://www.learningaboutelectronics.com/Articles/Atmega328-pinout.php
    You can see that pin 1 is near the divot on top of the chip. Pin 1 is also closest to the dot on the IC (although it’s not shown in the graphic). Pin 1 also has a square solder pad, where as the rest of the pins on the IC have round pads. From pin 1 count the pins down to 7 and 8. Please note the graphic is a picture of the IC from the TOP, but you will be soldering the cap to the BOTTOM of the IC, on the solder side of the board. So keep that in mind when finding pins 7 and 8 on the bottom of the board.
    Once you think you’ve found pins 7 and 8, test them to make sure you are correct. Pin 7 should be connected to the other 5v pins around the board and on the voltage regulator. Pin 8 should be connected to ground.
    Remember electrolytic caps are polarized so the positive lead (the long lead) should be soldered to pin 7 (aka 5v) and the short lead (the negative pin, with the white stripe on the body) should be soldered to pin 8 (ground).
    Cut the leads short and lay the body of the cap down on the solder side of the board so the leads are touching pins 7 and 8…then solder the cap leads to the IC’s solder pads. You may want to hold the body of the cap to the board with some hot glue or something to keep it from rattling around so the solder joints don’t eventually break.
    Please let us know how this works for you.
    Good luck!
    -Brach

    #25416 Reply
    mike335
    Guest

    Thanks for the guidance Brach. If I decide to add the cap, I’ll let you know if it helps.

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