[Sticky] USB-C Microphone (official topic)

@imp-inventor I built it myself, I can share the images and audio sample, but the I have reached the limit for attachments.

@muzammil17 If you don't want to hit the limit that's fine, you can always post it some other time--or not at all, if the attachment limit doesn't refill for a while. I haven't hit it before, so I wouldn't know.

@imp-inventor do you have discord? I can add you and share the audio and ribbon mic image.

@muzammil17 No, I'm afraid I don't have Discord. Is it possible to send files through the DM system here, or does the same limit apply?

@imp-inventor same limit applies.

@muzammil17 Bugger. Still, I'm sure it's a good piece of tech.

@imp-inventor I did upload a while back, the audio and the image of the ribbon mic.

You can route it via me - I think you both have my private email (don't worry folks, nothing weird to see here)... Unless you're into Simon and Garfunkle. (If you know...)

@marcdraco Yes, you and AI combined with Simon and Garfunkle makes a dangerously bizarre combination, to say the least 😉

Here it is,

 

@imp-inventor the ribbon mic (edit: wasn't) tuned much, and the phones speaker was 2 inches away from the ribbon mic, volume may have been less, i used the original diy perks pre amp and help from @marcdraco to modify the preamp to make the ribbon mic work.

So I'm tentatively beginning the process of building this microphone, and from talking to people in this thread I've deduced it would be better to build the updated version (Songbird Michelle 3.5 I think?) than Matt's original PCB design. Unfortunately, while I don't have any problem selecting parts and soldering them to a circuit board, I'm way out of my depth when it comes to printing boards. I genuinely have no idea where to start--JLCPCB seems to be a cheap, fast manufacturer--but I don't know how to get them to print the board. So if someone who knows what they're doing/built this could give me a hand, it would be much appreciated 😀 I'd hate to spend over 60 USD and discover I've done it incorrectly, and have to spend another 60...or whatever the price is to print this. 

Thanks!

Posted by: @imp-inventor

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So I'm tentatively beginning the process of building this microphone, and from talking to people in this thread I've deduced it would be better to build the updated version (Songbird Michelle 3.5 I think?) than Matt's original PCB design. Unfortunately, while I don't have any problem selecting parts and soldering them to a circuit board, I'm way out of my depth when it comes to printing boards. I genuinely have no idea where to start--JLCPCB seems to be a cheap, fast manufacturer--but I don't know how to get them to print the board. So if someone who knows what they're doing/built this could give me a hand, it would be much appreciated 😀 I'd hate to spend over 60 USD and discover I've done it incorrectly, and have to spend another 60...or whatever the price is to print this. 

Thanks!

You could always do it yourself at home. There's Youtube videos. You can use an iron to transfer a printout made on a laser printer, onto the board, then etch it with ferric chloride, or even a mix of white vinegar, liquid peroxide and salt. I think if you pay for a professionally made board, and you're only getting one copy, the total cost would almost double. Or you could just use vero board. You'd just have to figure out your own layout.

 

Sooo...there's one final twist in the story of my mic. It worked great when I first made it, but a short on the little Mickey Mouse USB interface, fried the DC-DC convertor and - it turned out, damaged the filter caps by varying degrees.
 Anyways, I got it all figured out. I got another DC-DC convertor the same as the original, because I had bought a 2 watt one as a replacement, and while it worked fine, I had to add more load to get it to work quietly.
 BUT...after returning the power supply to the original circuit, I tested the mic, and it worked great...then got noisier and noisier. 
 Sooo, I was already a little sus of the replacement caps I'd gotten. They're the Sanyo ones with the dark green case with gold lettering, but cus my mic only has room for 20mm tall caps, and I wanted to get 25v caps cus I feel like 16 is pushing it a bit when the rails are at like 14 ish, I had a hell of hard time finding anything. Soooo...yeah, I'm almost 100% sure the caps I got were fake/mislabelled. Cus I can't for the life of me find any other 2200uf 25v caps that aren't AT LEAST 12.5 x 25. So I took one out and weighed it, and it weighs 2.4 grams.(albeit with the leads snipped short) If the capacitance was ever accurate, then that puts it at the weight of a 10v cap. I opened one, and there's no obvious tricks. The strips are tightly rolled and a tight fit in the can, so i think it's just a cheaper cap with a lower voltage rating, that's had the shrink wrap from a far more expensive cap put on it. 
 I'd message the Ebay seller about it, but like all of them, it's just probably just some dude renting a storage unit on an industrial estate, buying stuff in bulk from China to resell.
 So...again...diagnosing the fault was complicated by yet another bunch of fake parts. But I'm absolutely certain those Sanyos were fake. So, I've had to order 1000uf caps, cus it's all that will fit. But I have room for 4 of them, so...almost the same capacitance, half the ESR. It's prolly better anyways.
 But can all you Ebay folk stop selling fake stuff! It's gotten ridiculous the last few years!

Fake a Rolex, by all means! Fake a Luis Vuitton handbag! But seriously! Can you imagine a shady bloke following you into a pub toilet and offering to sell you fake 2200uf 25v electrolytic capacitors? The can't be much money in that particular corner of the underworld.

@ashleigh Thanks for the reply, but I don't have access to a laser printer (very unfortunately). I assume when you say I could use a vero board, I would just buy all these parts individually and solder them myself to a stripboard? Do you think it would work with the smaller components used in the printed circuit boards, instead of the larger ones Matt uses?

@imp-inventor have you looked the other boards?

Actually 16v is very naughty with those DC-DC converters. Matt "got away" with it because the load on the 1W converter was such that it ran out of guts long before anything went bang. 2W... nope. That will push the rails to the max unregulated voltage which (I measured) can exceed 25 volts under "no load". Even a tiny bit of realistic load will pull that down to around 18-20 I would imagine, I haven't looked. 

But Murata does recommend 25 v rated caps for that module.

@imp inventor - I have some credit at JLC IIRC, might be enough to have a couple more beta boards run off and shipped out. Where you at?

@muzammil17 What do you mean? The other editions of this microphone?

@marcdraco Thanks for the offer, but when it comes to building stuff, I like to do as much of it myself as possible. Easier to quickly get experience that way.

@imp-inventor I built the alpha for testing, thanks to @marcdraco for providing the file, and it worked, It works perfectly fine, first try, just need to find or design a case for it.

@muzammil17 Assuming you had it printed, was it more or less expensive than the latest edition? (I think the latest edition is somewhere in the region of 60 USD to print from JLCPCB)

@imp-inventor

@imp-inventor a bit less than 60$.

@muzammil17 Huh. That doesn't look too complicated, actually. Or too expensive. Is that Matt's original design, or the first of the modified designs?

@imp-inventor I guess first of the modified designs, there have previous designs, but this is a improved version of the original.

I'm going to have to ask @marcdraco how good this design is compared to Songbird Michelle 3.5 but it looks like I'd be much more comfortable building that. No printing or laser cutting there, just good ol' soldering. Is there anything special about the base board all the components are attached to, or is it just a fancy stripboard?

@imp-inventor it's a fancy board as it is carefully built with screening in mind, it would take roughly 30min to solder everything up and test, my previous audio file was recorded using that preamp.

@imp-inventor you can plug in any usb sound card directly and power the amp using the same usb power of the sound card like I did, had no problems.

@imp-inventor the songbird Michelle 3.5 is going to be way more better, for sure, which might be a bit more expensive that alpha.

Posted by: @imp-inventor

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@ashleigh Thanks for the reply, but I don't have access to a laser printer (very unfortunately). I assume when you say I could use a vero board, I would just buy all these parts individually and solder them myself to a stripboard? Do you think it would work with the smaller components used in the printed circuit boards, instead of the larger ones Matt uses?

Nah, I assume you mean surface mounted parts? Deffo don't want to use those on stripboard. But there's almost always a through-hole equivalent. If you don't have access to a laser printer, you can actually draw the circuit on the copper board. Enamel paint or nail varnish works. There's videos on how to do it a bunch of different ways. Or you could shop around and see if someone can do it relatively cheaply for a one-off. Or maybe you could get 10 or more made, and sell the rest.
 I'm sure these days, though, the cost of getting a one-off board custom made has come way down. I'm sure there are services where you just email them the file, then they mail you the board.
 i'm not sure what board you mean though. I just went the stripboard route. it doesn't look as pretty, but it works about the same.