Do We Need/Want a BBD Tester?

Stickman393 said:
Negative, I got smacked with an OT weekend thats made my mush brain. Doodley doo.

Gonna try to get some more done this week.
Click to expand...
Fair enough and understood.

When you do get back to it, please consider that some may not want to use a large rotary switch where simple pad, pin and/or jumper scenario/access can suffice.

I'll keep my eyes & ears pricked up for your next response.
 
For sure. I've made a few changes in terms of cutting down the number of components, combining a few of those 4.7K's and 100K's as we're probably gonna never need to do more than one BBD at once.

I added a piano switch instead of the rotary: the pin spacing is such that if one wanted, they could use a double dupont header and jumpers if they so wanted to. I'm also thinking that r2 is redundant: we can get rid of that guy. Switched up the voltage inversion scheme to make sense. I looked at it today and was like "aw hell no".

Right now I've got board-mounted jacks, which do take up a bit of board space. Those are just placaeholders: I'm thinking the low profile variants that tayda sells would be better. Need to find out what those are called and get the footprints for them.

Granted, I can do multiple iterations. Swapping footprints is not a big deal. I could do a variant with screw terminals if somebody wants to cut down on the size. I'll try to get a bit more done tomorrow and might have a decently finished product by the weekend. We'll see.

Progress for today (keep in mind, the board layout is *just* a rough-in. It's gonna change a LOT):
Screenshot 2025-04-10 184951.png
Screenshot 2025-04-10 185049.png
 
Lovin' it! Lookin' good!

Redacting redundant components should not be an issue because the unit was only ever designed to test one BBD type at a time.

I'm guessing that when you say "piano switch" you're referring to a PCB-mounted DIP-Switch? If so, yeah, that would work nicely. It would serve well also to have the switches labeled directly onto the PCB; as well as for the BBD-type switch & LED indicators.

Excellent work. Thank you!
 
For sure! My plan would be to have that information silk-screened on the PCB. Each switch/led would have an indicator of which channel an "on" position would activate.

In reference to the type of switch, Tayda sells these:

Though a normal DIP switch would work just as well. I only selected the piano switch's footprint as it's easier to actuate those without a tool. That said: the parts are cross-compatible, and I can leave the outline off the silkscreen so OCD doesn't take over.

Truthfully, the most important part of this in my mind is going to be "what does the average builder tend to have on hand?". I want this to be easy to assemble with whatever somebody has on hand.

In terms of that:

1/4" sockets are going to take up some real estate, no doubt about that. I was thinking that these would be better to keep it compact:


That said, I could also design with mini jacks in mind if that's preferable.
 
I bought like five pairs of BBD on ali (MN3207 and MN3102) for $5. I knew it was a gamble but so far they all work (one is noisier)... Is there something specific to check when buying BBD to determine if it's good or bad other than testing it in the pedal? I know there's fake IC's out there but are there any "fake" BBD that would actually act like a BBD without being one?
 
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makisushi said:
I bought like five pairs of BBD on ali (MN3207 and MN3202) for $5. I knew it was a gamble but so far they all work (one is noisier)... Is there something specific to check when buying BBD to determine if it's good or bad other than testing it in the pedal? I know there's fake IC's out there but are there any "fake" BBD that would actually act like a BBD without being one?
Click to expand...

When buying BBDs, the best way to ensure they are genuine is to obtain them from a reputable dealer. Once in possession, the only way to be sure the BBD is genuine is test it in a known working circuit or a test jig - like the one we're making. This BBD Tester board we're working on provides only the most fundamental bits required to determine if the BBD is actually generating it's specified delay.

There's no such thing as a "fake" BBD that acts like a BBD. It either is a genuine BBD or it's a fake. And if it's fake, it will not produce what a BBD produces.
 
Screenshot 2025-04-20 163217.png

Questions, comments, concerns?

I added a few decoupling caps. It's not the most elegant layout, but it *should* work.

I still gotta add text and instructions and such to the silk screen layer.
 
A'ite homies: Here's the link.
Its taken me a while to get there.

I've included all the kicad saved files as well, so y'all can add, edit, to your hearts content. I've completed my task: it is now open for community edits and changes.

I've got the BOM, drill files, and gerbers in the link below.

Dropbox

www.dropbox.com www.dropbox.com
 
Stickman393 said:
A'ite homies: Here's the link.
Its taken me a while to get there.

I've included all the kicad saved files as well, so y'all can add, edit, to your hearts content. I've completed my task: it is now open for community edits and changes.

I've got the BOM, drill files, and gerbers in the link below.

Dropbox

www.dropbox.com www.dropbox.com
Click to expand...
Awesome! Thank you @Stickman393 !
Wow - looks like the entire file history. I take it the latest dated zip file are the Gerber to submit?
 
Yessir...the main folder is where the gerbers are. The backups are from various edits over time...you can go ahead and delete that folder if you want, it shouldn't make a difference.
 
Ha! I just sorted out that the zip files in the back up folder are archives of your progress. I just zipped up all the .gbr files from the main folder and submitted that. When it loads on JLCPCB, there is no silkscreen and the drills seem to be missing.
Really wish I knew PCB design software better.
 
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It looks like much of the intended silkscreen text is trapped in the FFab layer. All the text in the FFab layer does not show up in the Gerber view when submitted.
 
I was able to make the changes to the Silkscreen layer (to mimic the FFab layer text) and exported the Gerbers. Looks right now.
But holy shit! JLCPCB fabrication cost for 5 is only about 7 bux, but they want $70+ for shipping on their cheapest option. I went with OSHPark at $36 for 3 boards with free shipping.
 
Good to know! Still learning.

Yeah, tariffs have struck PCB fabrication. Crossing my fingers that they'll drop those soon. Oshpark is good too...they're who I'll be using in the near future.

I did end up figuring out that I dropped the drill file the backup folder accidently. I cleaned up the link and put together a pre-made zip file for it.
 
Weird, grand total on my JLCPCB is like 40 bucks for 5 boards. UPS shipping is like 23, customs is like 10.80. Still nearly twice the cost of the boards. Crazy.
 
In the original BBD Tester PCB, RV1 is 10K. While the 100K you have slated for RV1 should work, the sweet spot for biasing the clock chip will be extremely narrow and may be difficult to nail.

In any case, the schematic in the OP is now fully updated.
 
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