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re:VREF An audio signal swings both positive and negative voltage relative to ground. An op-amp can't amplify a voltage below the negative supply or above the positive supply. Most op-amps in guitar pedals have a negative supply of GND (0V) and a positive supply of ~9V. So pedals will supply...

Agree you need to check R101 and R102. The numbers on your ICs tell me that your VREF is totally wrong. Am I reading correctly in the list above that the voltage on IC3.2 pin 5 is 0.007? That's exactly what you'd expect if R102 was 10R instead of 10K (@micmac spotted this in #10). (7.7 * 10 /...

Oh, based on the schematic that looks expected. It looks like that half of the dual op-amp isn't used, so it's all just grounded to itself on a little island. (Sorry, I guess back to the drawing board!)

I have to underline the advice about the audio probe, in my (limited) experience it's been the most useful tool for diagnosing issues on my builds. It's really helpful to find the place on the circuit where the audio dies, it helps narrow down what part of the board you need to squint at. One...

Have you tried an audio probe, to see where the "good" signal dies and you pick up the noise? That's a super handy way to help narrow down the problem. Your soldering looks nice and clean. It's possible that there's something going on under one of the sockets, though :-( You could try to use a...

I'd love to see a pic when you are done - I wonder if the height and flexibility of the long pins will give you the room you need to maneuver the audio jacks where you need them. There's also this DC jack from Wurth electronics which I think is what the cheapie Taydas are modeled after, if you...

I saw that you were using the audio jacks with protruding barrels -- have you made a full size board like this with those kinds of jacks? One problem that I've had is that with the jacks protruding from the top, it's really hard to get the pedal into the enclosure because you can't get the pots...

Thanks for all of the feedback so far. I guess my experience with heavily-used USB-C ports is mostly with Mac laptops and those ports seem to be magical enough that I've never broken one despite a lot of jostling. I imagine there's a tremendous amount of engineering that went into that...

Apparently https://www.digikey.com/en/products/detail/recom-power/RO-0509S/2314944 is listed as a drop-in replacement. But they're pretty expensive! ( > $6 /ea ). I'm hoping to keep the per-port cost pretty low. There are some 1W DC-DC modules that are relatively inexpensive (~$2) that might...

I mostly got into building pedals to make stuff for my guitar playing nephews. The best I can say for myself is "well, I OWN a guitar". This year at Christmas, the younger of the two nephews was like, "Gee, Uncle @z2amiller, these sure are great but what I really need is a way to power a bunch...

Heck yeah! Screw soldering wires to things! The only problem with the layout + my drill pattern is that once you've soldered in the footswitch, the board isn't coming out unless you cut the headers that attach to the footswitch. That's probably fine. If I cared, I could switch to low profile...

I've added the templates to my github repo: https://github.com/z2amiller/pedalfx/tree/main/template If you want to use these templates, copy them into your KiCad template directory. ( Mine is in ~/Documents/KiCad/9.0/template ) I've put the control layout dimensions, the daughterboard...

Good News Everyone! As of about a week ago someone committed a patch to the Bouni KiCad tools to fix the in-app search functionality, and the components are searchable again. You don't need to update the plugin itself, but you do need to re-download the parts library ("Download", in the upper...

I forgot to mention before - I'd love to hear any other useful tips and tricks that folks have for improving their designs or their efficiency! Also, I forgot a couple things in the 'Mistakes' section (speaking of Mistakes): Label Pots and Switches Depending on which footprint you're using...

I've seen that sometimes. It looks like it's supposed to be connected to VREF. I assume VREF is on the top layer somewhere? If VREF is a filled zone, it's possible that your VREF zone is orphaned. e.g. your cap is connected to VREF zone but the VREF zone has been disconnected by a trace or...

Pitfalls and Tips: Designing effects PCBs Intro Following up on my ‘Getting Started with PCBA at JLC’ document, I thought I’d create something similar documenting some of my big mistakes and learnings from creating these PCBs. This isn’t my job or my background, I’m just doing this for fun...

Honestly this looks like a pretty standard power section to me. You could save some space by going SMD, especially if you're doing sandwiched boards if you need more vertical space. SMD caps and chips are going to be half the height or less. In KiCad you can have 'design blocks' that you can...

There's been a lot of 'ink' spilled on this on various forums. The general advice that I've synthesized is that MLCC caps are fine if you use NP0/C0G dielectric caps in the audio path, but that the other MLCC caps can be microphonic at audio frequencies (e.g. they can become both a microphone...

re: the weird IC voltages, that looks like it is correct for this circuit. Ideally, the signal in to an op-amp sits right in between the positive and negative voltage rails. The op-amp can be fed with a bi-polar supply, that is, a voltage that is positive and negative relative to ground...

Yeah - the pedalpcb 'standard' has the pots and switches mounted on the 'back' or non-component side of the board - so the pots stick through the enclosure and anchor the board in place, and the components are all visible. (which is handy for trimpots, internal switches, etc). If you were to...