A DIY microphone built using the design of DIY Perks and modified by me. I wanted a decent mic and I didn’t want to spend the money on one, so when I saw this video it seemed like the perfect opportunity for me to both have fun with a electronics project and get a decent mic.
This would not be possible without DIY Perks and the resources he provided. The stripboard and base wiring diagram are extremely helpful as well as his overall attention to detail. Video link here: https://www.youtube.com/watch?app=desktop&v=LoQu3XXIayc
For this build, there are a number of parts you will need. In the video he goes all out in brass, which for most of us at home, seems absurd because of how uncommon it is to have the exact diameter of brass tubing or brass mesh lying around. I ran into this problem early on, so I designed a box and lid for mine that should work in place of a ton of brass and wood and is easily 3d printable (STLs above). I know most people don't have 3d printers, but I feel like this is slightly more accessible for those without hordes of tools. I also used a mic arm I found in the trash to make the arm instead of building it. So, with the 'housing' out of the way, everything else can be found in this list (or at least what I used/needed):
https://docs.google.com/spreadsheets/d/1pQlkRerO5geoDNLEWXTUVbyJalM7nESn/edit#gid=497893649
As you can probably tell, the pricing is pretty high compared to the sticker price. That was the number I was able to get it down to after some alternatives (and using the wrong materials and finding out they don’t work. The electronics can either be found on alibaba or ebay, I chose ebay because that was the only way I could finish this in less then 2 months. With all of that, I nicked a old audio cable, a old rc car motor, and some resistors in order to start building.
The first thing I did (and this pretty much goes with the order the parts arrived to me) was the preamp box. I put some brass mesh on the bottom and glued the template on some protoboard, soldered all of the parts on and drilled corner holes. In hindsight, the pegs I included were pretty useless (and off center) so they should probably just be removed. I layered some tape over the bottom mesh to prevent shorts and plopped the whole thin in. I then added the potentiometer to the lid. Note, I live in the US, so I was unable to get a THAT1512, and I had to go with an INA217. This isn't really a problem, just know that on my final build, I attached a 2.2kOhm resistor to the potentiometer because of how the gain settings work. I assume there may be some overall gain differences, but we'll get to that in the review section. I pretty much did that and threw in the ADC (Analog Digital Converter) with some tape covering it. I ordered a pretty cheap one, but it has a led and I kind of like that because of how much easier it made troubleshooting. All of these parts can be connected to the main board and the ADC can be connected to the USB-C breakout board. Power wires can be connected and that should be everything that is directly connected.
Partially Assembled:
Some notes real quick before putting anything on the board:
The two capacitors on the right need to be flipped 180 degrees so the polarities are swapped, and all of the rest are fine, with the white being positive and dark being negative. Other than that, you can build it however you want. I found that its better to use a little bit thicker audio cable, because the stuff that i used was really thin and I ended up having to solder it a bit to get the connectors to stay on.
And on that note lets talk about the cables. So yes, you can use solder removing copper strips like he did. But I had extremely bad luck with mine all just being flat to begin with, and thus not folding back into a tube. So as a result, I just ordered some proper sheathing. Honestly, worth it. I ended up threading the enameled wires through much easier than I thought it would be. So, with those two out of the way, IU soldered them together and used a heatshrink for the binding. Now, I just want to note that the way DIY Perks sands the enamel off of those thin wires is correct, however, be extremely careful because if you go too far, they are super easy to short (trust me I know from experience). So, with that, you can plug the cable into the preamp and work on the mic.
The mic, from my experience, has the parts that take the longest to get here. First of all, if you can get a JLI mic module, be my guest, but they seem to be always out of stock. I ordered mine from another place for a significant markup and I'm not even mad. At least it’s here. The transistors took a hot minute to get here (they were the last thing I needed, and I actually moved on to another project I got so sick of waiting on them. Once they did arrive though, its pretty much exactly as he said. However, I should note my module housing is also 3d printed and the grills are shaped using 3d printed parts. Crushed the mesh in between the mold and formed the grills, soldered them with the transistor mic combo like a sandwich, and jammed it into the housing. I added all of those holes for maximum sound quality, and it seems to work. I will note that you should probably put something between the grill and transistor, as well as between the legs due to possible shorting, as that is what caused a lot of my early trouble. With that, that’s basically everything. I used some tape to secure the lid onto the box and hot glue to keep some loose things secured and it just kind of works.
The rear of the module is really jank for me. Don't do this lol:
Overall its a good mic. I've been using it for the past few weeks and everyone who’s seen it really likes it. It's kind of scuffed but sounds fantastic (most of the time). I should note that I had a insane amount of gain until I added a resistor between the potentiometer. I still do, and I probably just need more shielding, but it sounds fine over discord and for personal use so I don't mind too much. I'll fix it when I need it.
The big things about this project I would note for anyone looking to do this is that a.) it costs more then you expect, b.) it's not going to look anything like the video, and c.) there will be more noise then you think there will be. Other then that, happy building!
Hello, I thought I was done with this project but let me tell you I've got a update that may interest you. Back when I was picking out the parts for this, I chose to use a INA217 because it was available and the only way for me to get a THAT1512 was a long 4 month wait from the UK. So, I bought the THAT1512 and the INA217 and hoped it would work out. I used the INA217 for the past few months and I can say its definitely good. Not great, not bad, just good. And I was happy with that. I had to use a higher resistance resistor in place of the potentiometer but overall, I didn't really mind it. There was a little bit of background noise at some frequencies, but I just thought that was my bad shielding.
I just got my THAT1512, slapped that bad boy in there and let me tell you, it's a whole world of difference. The two chips should be very electrically similar according to their data sheets, with only a little bit of gain differences, but the difference is insane. No more noise went back to the potentiometer, better volume (even at the same levels), and overall, a better time. Anyway, hope that interests you. They're kind of hard to find so if you can get one then do. Otherwise INA217 is still pretty good.
Hello! It has been a while. I never thought I'd update this repository again, but I just wanted to stop in after a while and clean up by bringing some modifications to the original project and overall design. I found the original mic design to be pretty cool, but horribly inconvenient to use. I ended up switching to another microphone for a while, but I thought I'd come back with some real quality of life changes to make this actually usable for me. The main things I changed were swapping the housing for a BM-800 microphone body (one of the worst sounding mics on the market - but cheap to fit with the theme) and designing a PCB which follows the original stripboard. My PCBs totaled a cool five dollars, and the quality of the entire thing is significantly higher.
The end result was much better than the original, with significantly less noise and much more versatility. I added the KiCad files to the repo but don’t expect too much. I found the mic gets a bit hotter and has a much lower gain setting (100 ohms) due to the lower noise but is overall pretty good – especially when compared to the original. These upgrades make this 99% more usable for me and hopefully if you either still use this project or something similar this update is helpful.
