Any ideas?

[MicMaven]

In the spirit of DIY, I acquired a couple of very low cost microphone circuit boards, notwithstanding I can find no specific information about them. I do not mind experimenting, but I hesitate to just hook a bunch of capsules to them before asking if anyone can provide some clue as to what type is most appropriate. I just loathe the prospect of letting the all-important functional smoke out by an inappropriate pairing. So, before I try my best guess, perhaps someone can suggest what type of capsule I should try first? Hint: My objective is to build a home-brewed pencil style condenser like the one I built last Summer and disclosed in this forum.) While I am interested in knowing more about both of them, the second one with the three XLR pins is my first choice to start with, but I am unsure whether these are intended for low bias voltage from a sound card or 48 volts phantom power from a mixer. I am also unsure whether I need a FET type electret capsule, or can use one with the FET (like a left over BM-800 type capsule). (I am still a novice in reading schematics and analyzing circuit components, hoping to learn more as I go along.)

Thanks in advance for pointing me in the right direction. James

 

[Drosselmeier]

1. for electret capsule, battery powered
2. for electret capsule, 48V phantom power, standard BM-800 circuit

 

[Rob Flinn]

They look like the ones I bought for my diy pzm mics, which are for electret capsules.

https://groupdiy.com/threads/diy-budget-pzm.86252/

 

[MicMaven]

THANKS GUYS for the quick replies!

Mr. @Drosselmeier -- Your assessment matches my own take. I just wanted to be sure before I connected a low power board to 48v and let the smoke out. I suspect the first, smaller board should work with a computer sound card, while the second, larger requires, as you indicate, higher voltage (although I understand the BM-800 circuits typically work, with diminished performance, with computer sound card bias voltage.)

I appreciate the BONUS image - schematic drawing you provide.

Mr. @Rob Flinn - Yes, the second image is similar, if not the same, as what appears in your PZM project photos - although I suspect your project has the brown-colored PCB Board material, while these have red-colored PCBs. I used the brown type in several of my own home brewed small condenser microphone projects with pleasing results. One of my previous projects is discussed here:

https://groupdiy.com/threads/a-man-needs-a-hobby-right.86475/

The OBJECTIVE of this project is to use a BM-700/800-style FET-LESS electret capsule in a similar build - whereas the former project employs an FET type electret capsule. I believe this will provide a similar, yet somewhat different sounding result and cost very little. The two microphones will be essentially the same in other respects.

Thanks for the confirming replies. James