Mods here: Bazz fuss, electra distortion ect.

[OiMcCoy]

With a printed PCB, should proximity not be any issue? Or is there a serious tolerance issue?
I only ask because this is my latest monstrosity...

[iainpunk]

With a printed PCB, should proximity not be any issue? Or is there a serious tolerance issue?
I only ask because this is my latest monstrosity...

its full of to-close tolerances, its not about making phisical connection, but capacitive connections can also really freak things out.
there are also some not connected components in there.

cheers

[OiMcCoy]

So what is the minimum tolerance then?

[bluebunny]

Tolerances will be defined by whoever fabricates your board.  They will publish their own set of design rules.

[iainpunk]

Tolerances will be defined by whoever fabricates your board.  They will publish their own set of design rules.

yes, but even when adhering to the rules, you can get oscillations, or changes in tone.
a rule of thumb i was taught is 1/3rd of the track width you use. also, remember that pads are way bigger that tracks!

cheers

[Fancy Lime]

In KiCad, go to Setup, Design Rules. There you can set the global track width and clearance. You need to put the same numbers in the respective fields for Diff Pairs ( width and gap), else KiCad throws an error and won't take the changes.

I used 0.4mm clearance and 0.8mm tracks on my current design. Looks ok to me.

Andy

[OiMcCoy]

Thanks for the advice everyone!!!

[Marcos - Munky]

With a printed PCB, should proximity not be any issue? Or is there a serious tolerance issue?
I only ask because this is my latest monstrosity...

Aside from possible parasite capacitances and other stuff, my main worry is this one. When you send the board to be fabricated, they'll add masks insulating all the traces, and leaving only pads exposed to be soldered. The tracks and pads indeed can be too close but not touching each other, but what happens if somebody is soldering that pad happens to damage a bit the track insulation mask (by excessive heat or by acidentally scratching the mask with the soldering iron tip)? You'll have a bit of the track exposed. Maybe it doesn't mean anything, or maybe somebody can make a solder blob that shorts the pad and the track and the effect won't work. Better safer than sorry.

I believe a "safe parameter" for distances is to look at your layout and think if it's possible for you to etch it at home. I mean, some people can't etch a double layer even if it's way simple (me), but you can thing on each layer as a separate board, just to check the traces. If you think you can't do it for some reason, then try to fix it. If you think is doable, then go for it.

Also, most of your monstrosity tracks can be easily "fixed" if you make bigger the distance between some tracks and pads. The hard work (layout itself) is already done.

[OiMcCoy]

Thanks for the advice. Sorry to hijack this thread, but its been very helpful for me.

Here is the redux of the layout.

[Marcos - Munky]

It looks better. Just 2 more things:


- Left side blue square:don't know if those two pads are supposed to be connected. But the red trace that's connected to the left side of the top pad is too close to the bottom pad.
- Top right corner blue square: the red trace connected to the left pot pad is too close to the other 2 pads. You can see there are dotted lines between those two pads and the red trace, those dotted lines indicates dimension/position issues and appears when two things are too closer or overlaps one against the other.

[Fancy Lime]

And there seems to be a connection missing near the bottom right corner.

BTW, how do you export these images from KiCad. I can "plot" them alright but only layer by layer and only black and white. If I "print", the PDF version does not work at all and the SVG version looks strange with transparency where there should be no transparency.

Cheers,
Andy

[OiMcCoy]

Thanks guys! super helpful stuff as always.

Also I am just screen grabbing the images. No exporting going on. Might also be why they are potato quality.