PCB Manufacture - 1 offs/low volume

(Doug Hammond) #1

Hi all,

Some of you may know I’ve been designing a semi-modular synth. I’ve given up on the idea of completely hand-building the circuits as it is too laborious, therefore I have made PCB layouts in KiCad and I want to get these made:

(each board is 200mm x 150mm)

This would be the first time I’ve had PCBs made.

I’ve come across this manufacturer - https://jlcpcb.com/quote - which has a minimum quantity of 5, however the price seems quite reasonable (£14 per design for 5 boards + £7 shipping).

My questions about this are:

  • Does anyone wish to check my layouts for noobie errors? :wink:
  • Has anyone used this particular manufacturer before?
  • Should I look elsewhere?
  • If I get more boards made than I need, would anyone else be interested in a set for a small fee or donation to SLMS?
    – The boards implement these modules: 4x VCA, 2x ADSR, 2x VCF, 2x LFO, 2x VCO - all YuSynth designs running on +/- 12V.

This is a key stage in this project, getting these made will obviously accelerate me towards completely finishing the project - which has been in progress on and off (mostly off) for about 4 years :stuck_out_tongue:

Any help would be much appreciated.


(unknowndomain) #2

There are loads of PCB fabs:

Before sending it off, run an ERC and DRC, check that you’ve got a ground plane, and do a laser print and check the main components that have unusual pad shapes line up with the print.

(Robin Baumgarten) #3

We’re getting an order from JLCPCB with some other peeps from the Makerspace soon! You’re very welcome to join and split the shipping with us! I guess we’ll order in the next week or two.

Also, I’ll be in the space pretty much every day for the next two weeks and are happy to have a look over your PCB files! I’m not an expert yet either, though

(Doug Hammond) #4

Ok cool. I may pop in Thursday evening then if you’ll still be there around 6 ish?

(Robin Baumgarten) #5

Sure thing, I’ll be there!

(Andrea Campanella) #6

I noticed you have a lot of T type connection , that’s usually pretty bad , especially for audio application , if I were you I would connect the tracks with a different angle , like 45 degree , avoid sharp turns…

(Calum Nicoll) #7

What do you mean by bad? I think you might have it confused - 45 degree angle is not what you want due to possibility of acid trap but otherwise T is fine at sub GHz speeds, although you could also use Y. Unless you mean bevelling the T joint like this https://electronics.stackexchange.com/questions/82093/how-do-i-create-beveled-t-intersection-traces-in-eagle-cad

@doug As a general rule - I’d make your traces wider - you have lots of space and will make it easier to change - especially if any of these parts are drawing significant current.

(Calum Nicoll) #8

Also - have done maybe 100 orders with JLCPCB and generally find them excellent. allpcb are also good.

Ragworm.eu are not good, had a lot of hassle with them/generally sloppy e.g they incorrectly measured a board and didn’t mention it, and the boards were generally not that good - and generally slower to order from them than to get boards from china and DHL.

For pricing, especially if you’re doing something more unusual, pcbshopper.com does price comparision across all these manufacturers and more.

(Doug Hammond) #9

How critical/useful is this for audio circuits? Also, doesn’t that require an additional PCB layer?

I presume you mean to avoid track angles less than 90 degrees? I have done so as far as I can see. There are instances of 135 degree joins, but there shouldn’t be any less than 90.

I see plenty of T joins in other people’s audio schematics. I’ll take this as the prevailing opinion :wink:

Thanks, I’ve been over the layouts today to increase all tracks to 0.5mm + a few necessary adjustments to ensure clearances. I don’t expect any circuit to draw significant current, this is all audio signal level stuff.

That’s good to know :slight_smile:

Thanks for the advice so far. I will come to the space Thursday evening if anyone wants to see these designs and talk about audio electronics and PCBs :slight_smile:

(unknowndomain) #10

I am not in anyway an EE, the guidance generally says use one always, thats done by creating a flood fill of your PCB and most software will keep away from the traces so you wouldn’t need another layer no.

(Pete Hellyer) #11

In my experience, having one also drastically reduces the complexity of routing. As a side point it may also help you identify redundant components that might be missed in the circuit diagram

(Paul Court) #12

I’ve used https://jlcpcb.com and found them very good.

My one criticism was that the pads come up a bit small. Although its mainly a photographic process, their software does interpret the files so there is room for error.

like above, double and triple check the files, look at them on the jlcpcb portal as their software did drop a line on mine. Defo run ERC and DRC using known good manufacturing versions (I have Sparkfun’s versions somewhere) before you upload, this will fix some issues too.

Main message is that you cant check too much.