For everyone building these kits:
DIY means each one of you is in charge and doing all the work yourselves. We only provide a framework for you to build on. Adjusting the circuit and tuning the final sound of your microphones, is something you need to do by yourselves. Same applies to every microphone build on this forum.
And maybe this wasn't as obvious as it should have been, but the transformers available for this project do not sound the same. None of the 3U builds will sound the same as the Cinemag builds or the AMI builds.
In practice that means you'll need to make adjustments for each transformer build. If you don't know how to adjust the circuit, or even where to start, this thread is the perfect place to figure it out together.
And this should have been clear from the beginning:
Just because there isn't any complicated wiring and you're not fiddling with power-supplies, doesn't mean this is an easy project.
Every microphone build is complex, and needs a good grasp of how every component interacts with each other, along with a bag of tricks to get everything to sit where it's supposed to. Less demanding projects like this one are a great way to learn how things work, but you still need to apply the same process as you would to much bigger builds.
For e.g., in a tube mic you can adjust the cathode bypass capacitor, the coupling capacitor and the grid resistor to tune the low-mids and lows. So how do you do it in a FET circuit, when they aren't that different? What happens to the balance of a microphone when you remove bass?
Just remember almost everything in this circuit can be adjusted. You don't need to stop at what we've provided, it's DIY. Try different capacitor materials. See if there's any difference using a FET that needs a low source resistor vs the high resistance you're using now. Remove parts and see what happens. Even try a different transformer if you can't make another one work. Because this project will reward however much effort you put in – it's those who weren't afraid to try different things who reported the best results. Again, all of this applies to every build on this forum.
Otherwise, if you want something that performs well with minimal work, then we suggest using the Cinemag 5722. This kit was designed using that transformer. But until you adjust the balance of your 3U builds, you won't know what it's capable of.