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[Sticky] USB-C Microphone (official topic)

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JustAlbin
(@justalbin)
New Member
 

Hi there, new to the forum and was trying to build the mic but got stuck at the 2200 if caps, I’ve attached pics showing cap 3 and 4 with the polarity’s not matching the schematic! Am I reading this wrong or are they wrong on the perf board ?

thanks in advance 

Albi

5F74EC1C 7ADF 4984 916E 739FBECD1A6A
A0255E1F 0C7F 475B B008 4D0009E85C30

 

 
Posted : 19/05/2022 6:53 pm
RedRevo117
(@redrevo117)
New Member
 

Hi, 

I finally got around to getting my mic setup to where i can test it and im having a couple issues, ive had it mostly done for about a month.

1. I dont quite see how im supposed to have the 3 wires going out of the audio interface that goes into the 2 pin connector, do I just hook the white and red wires to go out?

2. I will be adding a volume knob but lack the proper resistors atm, I suppose I can just add a resistor on the 2 gain pins, any recommendations on what ohm resistor i should use

(I currently have a 470 ohm on it)

3. The biggest issue is the mic isn't picking up my voice, the only time I noticed it pick up anything was when it was sounding like it was being shuffled around it sounds like wind/static all the time. and if I tap it hard it makes a pop noise then goes silent and then after a few seconds it goes back to ambient static/occasional shuffling noise

basically when its just a ambient hum it does not pick up my voice, when there is static and shuffling then it picks up my voice which again is random

 
Posted : 24/05/2022 9:24 am
thijnmens
(@thijnmens)
New Member
 

I've fully assembled the microphone and pre-amp, yet the sound i am getting from it is no-where usable, it sounds like this:

 

anyone know what could be causing this?

 

Edit: I removed the 2 capacitors that are linked to the NMA0515SC and that made it worse, this is making me suspect that it's something with the counterpart I'm using, everything is the same except the USB to analog converter and the voltage booster (i am using a MEA1D0515SC)

 

This post was modified 3 months ago by thijnmens
 
Posted : 24/05/2022 2:36 pm
Jacobus
(@jacobus)
New Member
 

@diyperks I see the old community post for the XLR cable is not accessible anymore. Would you be able to provide the old schematics?

 
Posted : 24/05/2022 3:44 pm
RedRevo117
(@redrevo117)
New Member
 

 

I seem to have gotten the microphone to work for the most part but it randomly starts making a static/white noise sound nothings being moved around when this is happening its just happens while it just sitting there.

Anybody got any ideas on what could be causing this

edit: after posting this it started doing it all the time...

This post was modified 3 months ago 2 times by RedRevo117
 
Posted : 25/05/2022 6:50 am
thijnmens
(@thijnmens)
New Member
 

For those interested, I've made a PCB for the pre-amp, for those who are interested here is the link to the gerber (uploaded to google drive since the forums did not allow me to upload zip files)

 

This is the first time i have designed a PCB but i am pretty confident I've wired everything up correctly. Feel free to use and improve it

image
image
 
Posted : 26/05/2022 9:55 am
graydon.t
(@graydon-t)
New Member
 

@justalbin I was confused about this too but if you watch the video when he puts the whole thing together you can see the correct orientation of the caps.  You seem to be correct about cap 3 and 4.  That being said, mine still isn't working correctly.

 
Posted : 03/06/2022 11:53 pm
ElectronicNewbie
(@electronicnewbie)
New Member
 

Hi, I'm new to this and this is my first time trying something like this. What type of audio cabled does He use to connect the copper wire to the stripboard. Also what type of wires does he use for the rotary switch and usb-c power connections, connecting the usb audio interface to the Preamp.

Thanks in advance!

 
Posted : 04/06/2022 10:14 pm
graydon.t
(@graydon-t)
New Member
 

@electronicnewbie The audio cable would be 2 conductor shielded.  I ended up using a shielded aux cable I found on amazon.  As for the other cable, the usb audio interface comes with a pretty long usb cable and I'm pretty sure that's what he used.  You end up cutting it off anyways if you are adding the usb-c, so you may as well put it to use.

 
Posted : 05/06/2022 1:22 pm
BvE
 BvE
(@bve)
New Member
 

@justalbin @graydon-t

Hi Albin

Thank you for the pictures. I am a little stuck at this point myself.

My interpretation: The video is correct. The schematic mixes up the polarity of what you call cap 3 and 4. The print layout uses gray half-circles and I think the ones for caps 1 and 2 are inverted.

Your pin-out of the dc converter has a different polarity than in the video. The 15v + and - are reversed. I could not find a source for the pin-out so am assuming the video is correct.

What do other people think? I am no expert and would be very grateful for someone to check my thinking here.

 
Posted : 06/06/2022 1:32 pm
ElectronicNewbie
(@electronicnewbie)
New Member
 

@graydon-t Thanks!

 
Posted : 06/06/2022 3:47 pm
Ronflocos
(@ronflocos)
New Member
 

@diyperks Would it be possible to be a little more specific on the audio connector? I can't figure it all out

 
Posted : 06/06/2022 5:21 pm
BvE
 BvE
(@bve)
New Member
 

@diyperks 

Hi, thanks for the awesome video!

Could I follow up on the shielding?

You say just connect it to the ground pin. In the video it looks like you bend away the shielding from the audio cable.

Must there be a connection between capsule, brass shield, copper mesh, all the way down the audio cable to the ground pin on the circuit?

And follow up: this ground pin then shouldn't be connected to the shield of shield around the amp circuit, correct?

 

Kind regards,

B

 
Posted : 07/06/2022 3:55 pm
Ray
 Ray
(@ray)
New Member
 

@bve @justalbin

Greetings.

I stumbled across the same issue with polarity so I went to "mouser" after searching online for the NMA0515SC chip.

They have like many other vendors the datasheet attached in the description.

On Page 7of9 it states on a 7-PIN SIP (SIP meaning one column , there is also a 2 column version)
the pins are:
 
1:  +V in
2:  -V in
"3": its the empty space, no Pin
4:  -V out
5:  0V
6:  +V out
"7": also an empty space, no Pin
 
As I see it , the Pin-description at 12:11 in the DIY-Microphone Video is wrong.
 
Guten Abend/Good Evening~
This post was modified 2 months ago by Ray
 
Posted : 07/06/2022 7:48 pm
Barchel
(@barchel)
New Member
 

@diyperks hey, the old forum errors out when trying to access the xlr page is it possible for a resend of the xlr circuit

diagram?

 
Posted : 08/06/2022 12:40 pm
wyrdone
(@wyrdone)
New Member
 

In your materials page you specify the sizes for the brass tube. But not the thickness of the brass sheet.

1mm? 2mm? or 3mm?

 
Posted : 08/06/2022 8:06 pm
Parker
(@parker)
New Member
 

@graydon-t 

I am also using the J111 transistor and am getting similar results. I see sham had a few solutions for you and I'm wondering if any of them worked for you?

 
Posted : 10/06/2022 3:48 am
Ronflocos
(@ronflocos)
New Member
 

@parker i have a problem with the capsule, when i plugged into the enter, i have a big buzz without any acoustic sound, when a speak into this, i dont have sound which enter.

Can you help me and give me some advice please ?

Its either the capsule or the transistor is faulty

 
Posted : 11/06/2022 11:11 am
graydon.t
(@graydon-t)
New Member
 

 

parts

@parker Before I saw his reply, I had already swapped to the transistor he uses in the videos and it made no difference for me, almost an identical result.  I tried replacing the two 2200ohm resistors with the 1k resistors and It made the results worse.  I am also using a EC1SA05N, but I compared the data sheets and as far as I can tell, they are almost identical.  Maybe I'm wrong.  These are the parts I am using besides the transistor.

This post was modified 2 months ago by graydon.t
 
Posted : 12/06/2022 2:24 pm
mathewbaldwin05
(@mathewbaldwin05)
New Member
 

@diyperks do you have the schematic for a way to phantom power this via xlr? It seems your xlr schematic is down.

This post was modified 2 months ago by mathewbaldwin05
 
Posted : 12/06/2022 9:43 pm
DIY Perks
(@diyperks)
Estimable Member Admin
Topic starter
 

Here's the 'alice' version that's been floating around for a while. I've not tested it myself but apparently it works pretty well!

alice schematic
 
Posted : 13/06/2022 4:21 pm
Barchel
(@barchel)
New Member
 

@diyperks Thanks! 🙂

 

 
Posted : 14/06/2022 8:05 am
Ronflocos
(@ronflocos)
New Member
 

@diyperks Hello, I'm at the end of this mic design project, and I currently have 2 issues, I have to turn in this project by next Monday in addition to that. When I connect my capsule to the input I only receive buzz, yesterday I had sound with my voice for the first time, I don't know why it worked, then as soon as I connected my potentiometer, the buzz has returned. In addition I think I have incorrectly connected my potentiometer, with its 3 connectors, would it be possible to have help please?

 
Posted : 14/06/2022 11:39 am
JSDavis
(@jsdavis)
New Member
 
Posted by: @thijnmens

For those interested, I've made a PCB for the pre-amp, for those who are interested here is the link to the gerber (uploaded to google drive since the forums did not allow me to upload zip files)

 

This is the first time i have designed a PCB but i am pretty confident I've wired everything up correctly. Feel free to use and improve it

image
image

I have have done something similar but have added a audio out daughter board. I have finally got the main board made and am still waiting fir the rest of the components.

Iv attached some of my designs and the final board.

EasyEDA files main audio board

EasyEDA files headphone amp and speaker preamp daughter board

2BA0ED92 E78A 42B1 8F06 45C71C940564
D95F0838 1CE6 4058 A9BC 29905E8F4859
C42F0910 AA9B 4FDC A36F 5CDC2908A291
396684C3 7AF1 450D ABD2 D8DF3C658E4A
768F46AA 65F3 4995 A068 EE2C0622D2B1
7D3D1D5E 0F14 4A3C 8DC8 FB634BFE57E6

 

This post was modified 2 months ago by JSDavis
 
Posted : 14/06/2022 7:27 pm
Ismail
(@ismail)
New Member
 
Posted by: @diyperks

Building a USB-C Microphone

-official topic-

 

Microphones are ubiquitous in modern life; they can be found everywhere from your smartphone to your TV remote. However, the audio quality on offer varies wildly depending on their intended use, with studio microphones unsurprisingly being highly tuned to provide pleasant and detailed sound capture... but at a significant cost.

This is fair enough... all that R&D needs rewarding, right? Absolutely, but purchasing a $500 microphone only to find that it uses about $20 of easily-sourced core components is a bit of a painful discovery. This price disparity is one of the key reasons that building a microphone yourself can make a lot of sense. Not only can you customise its design to your specific use requirements, but it can cost significantly less than purchasing one pre-made. It's fun too!

This project covers everything from sourcing a good-sounding microphone capsule to building a frame for it and even including a USB interface so it can be used on any modern device whether that be a laptop or a smartphone.
 
 

Hi, I am having difficulty finding the right components for this build, especially with the transistor 2n4416A i am not able to find the same transistor as the one used in the video can anyone help me find a transistor with same specs as the 2n4416A.

 
Posted : 17/06/2022 5:51 pm
Ismail
(@ismail)
New Member
 

@graydon-t hey could you say which transistor did you use cuz i am not able to find the transistor used in the video.

 
Posted : 18/06/2022 4:27 am
Ismail
(@ismail)
New Member
 

hi, could anyone send me https://drive.google.com/drive/folders/1jQY1SycV0OChw9_9w9qhMVCW47YFHgBu a pcb design for this version cuz i already have the parts for this and idk if the other pcb's posted over here uses the same material's as in this. Thank you

 
Posted : 20/06/2022 8:26 am
huog-
(@huog)
New Member
 

Is there any othertransistor that would work? Where I am located the 2N4416A would cost upwards of 13dollars whice seems steep.

 
Posted : 22/06/2022 9:15 pm
tekken
(@tekken)
New Member
 

@justalbin

@diyperks

@ray

 

There seems to be a mistake regarding the NMA0515SC wired to the 2200uF caps.

12 minutes into the video DIY perks explains the -15 and +15 volt pins but this is the opposite of the schematic. I assume that was a mistake.

What makes this even more confusing, it is negative 15 voltage i should hook up to negative on cap, that means positive on the cap is hooked up to ground whis seems wrong. But is correct?

Can someone confirm that negative 15 volt should go to negative on cap and positive 15 volt to positive on the other cap like my picture. 

circ

 

 

This post was modified 2 months ago 2 times by tekken
 
Posted : 01/07/2022 10:51 am
Levieuge
(@levieuge)
New Member
 

Hi, I have a question about the 22 uF capacitors. In the BOM they are specified as non polarized. In the video radial capacitors were used which to my udnerstanding are mostly polorised and can be quite hard to find non-polorised ones.

Could I use cermaic disc capacitors instead or would that impact the sound quality?

 

Thanks in advance!
Eugene

 
Posted : 03/07/2022 9:35 pm
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