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  1. z2amiller

    Getting Started with PCBA at JLCPCB

    I've been adding some THT parts to all of my designs. Sometimes box film caps for larger values, and always JST connectors for the footswitch board. It adds a bit of cost (since there's a $3.50 THT setup cost even if you just add one component) but it's worth it to me for time savings. I...
  2. z2amiller

    Panelizing and having break-off parts produced.

    Couple of things: - If you have it done with PCBA, to use their 'Economic' service, you'll need to create the panel with mousebites instead of V-cuts which also means that you need to panelize it yourself rather than using the built-in JLCPCB panelization feature (which uses V-cuts). You can do...
  3. z2amiller

    Park and ride, signal not getting through

    Yeah - TL072s are relatively cheap in quantity and they're in almost every pedal. And if they're not in the pedal, a lot of the time they can be subbed for whatever opamp anyway - dual opamps have a standard pinout so things that call for NE5532, RC4558, etc can generally at least function with...
  4. z2amiller

    Getting Started with PCBA at JLCPCB

    I built a board using through-hole components and wanted to see what the JLCPCB assembly would look like for a purely through-hole board. For purely through-hole, there's no setup cost and no stencil fee. However, the cost-per-unit for assembly is a lot higher. For really small runs of boards...
  5. z2amiller

    Chaos Machine circuit noise

    It's possible that's an issue - are the other pin 8's also noisy? (There's a small resistor between which might help the noise though). IC4 is part of the LFO (low frequency oscillator) so it's not super unusual for stuff in there to make weird noises but it is odd for the VCC pin itself to be...
  6. z2amiller

    Help needed to design OD1/OD2 pedal from MG100DFX Amp

    I haven't gotten this all breadboarded, but I just yolo'ed a through-hole PCB layout and will order a stack of 'em next time I order from JLCPCB, and see how it works. If it makes any reasonable noises I'll release the gerbers for people to try out.
  7. z2amiller

    Klon Woes

    Worst case you can probably just bend those pins out from the socket (cuz you used sockets right?) and bodge it to VREF somewhere. If you did SMD or soldered right to the board it'll be a little harder, but should be at least hackable without getting new PCBs made.
  8. z2amiller

    Klon Woes

    I think pin 3 and 5 of IC2 should be tied to VREF (Vb) and not 9V. (9V maybe a holdover from using a charge pump where it was halfway between 18v and gnd?)
  9. z2amiller

    Chaos Machine circuit noise

    Good thorough notes! I think there's something wrong at IC2/3. That pin is tied right to VREF_A and other things that are tied to VREF_A seem to be okay, but that one is ~zero volts - so either it's floating unconnected or it's near-shorted to ground. Check your socket there there there...
  10. z2amiller

    SOLVED Yet Another Kliche Situation (Bypass is not awesome)

    I think something's wrong around VREF. Pin 3 and 5 of IC2 (middle) are both tied directly to VREF and they're showing 3.5V instead of something around the 4.7V mark I'd expect at 1/2 of 9.45V. Pin 3 of IC1 (right) is also tied to VREF through a 1M resistor and is only 1.16V which would muffle...
  11. z2amiller

    Chaos Machine circuit noise

    Pictures of the soldered side would be helpful (though of course kind of difficult to see everything with the pots in the way). Pot in bottom right of picture looks suspiciously soldered. (Middle pin may not be making contact). Dunno if that'd cause those specific issues or not. Really all...
  12. z2amiller

    A new-production BBD, with added features!

    I was trying to to figure this out, too - I think what it means is that in the "classic" BBDs there are two separate clock pins that step back and forth, leading to potentially more complicated offboard circuitry, where this chip just has a single clock pin that expects a square wave input...
  13. z2amiller

    Beginner confused with BOM

    If the BoM doesn't specify, it's probably fine. You could socket the transistor if you _really_ wanted to try to tune it, but for most pedals, something in the general vicinity of the gain range will be fine. There are some designs where it's important to have one transistor with less gain...
  14. z2amiller

    Beginner confused with BOM

    Regarding the transistor, the letter at the end of the transistor often indicates the gain range of the transistor. Manufacturing transistors is somewhat inexact and the gain can have a pretty large range of values. Manufacturers will do 'binning' where they test parts from each batch and sort...
  15. z2amiller

    SOLVED Paragon Mini - no sound on either side when engaged

    I think your vref is off. Looking at R12 and R13, they should be the same value (47k) but the multiplier bands look like different color - R12 looks like it might be 47K (Yellow Purple Black Red Brown) and R13 looks like 4.7k or even 470R, the lighting is not great (Yellow Purple Black...
  16. z2amiller

    Noisy PCB, breadboard version silent

    Have you tried it out of the enclosure, like just moving the input wire out of the way? (Rather than going thru the hassle of shielded wire). I think that'll help figure out whether or not shielded wire would help. I think running near/over the 9v rail is probably ok, though maybe not...
  17. z2amiller

    Help needed to design OD1/OD2 pedal from MG100DFX Amp

    @Reconciledheart I did play around with this on the breadboard a bit this weekend for funsies, with a bipolar supply (+9/-9V). I got as far as the main gain stage, I haven't gotten through the whole tone stack part yet. I might try it again next week with a unipolar supply + vref to keep the...
  18. z2amiller

    Noisy PCB, breadboard version silent

    With an audio probe, can you see where the hum starts? It might be helpful to find where the hum starts so you know where to focus your efforts. I think you could keep more of the backside routing on the top to keep a more continuous ground plane on the back (e.g. it looks like vref could be...
  19. z2amiller

    Help needed to design OD1/OD2 pedal from MG100DFX Amp

    I played around with this a bit, trying to make it a unipolar supply (just +9V) which looked reasonable given the clipping diodes in the main gain stage anyway. (caveat: I have no idea what I'm doing) When I simulated it in kicad I got all kinds of trouble, tho, but I'm not sure how much of...
  20. z2amiller

    Getting my learning on

    Install KiCad and download a bunch of build docs. Transcribe some schematics and practice doing your own layout! (Start with something easy like a Zendrive clone or a Acapulco Gold clone. (Put that learning to practical use! It's harder for me, at least, to just book read without also Doing...
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