OPEN SOURCE DIY Mic Project - ORS 87 - Stripped Down u87

[pasarski]

Hello, I forgot to order the LSK189-TO-92-3L-BK . Can I also take another one or will there be problems? I still have this one here bc239c https://www.mos-electronic-shop.de/239c-p-1791.html
BC 172
https://www.radiomuseum.org/tubes/tube_bc172.html?language_id=1

Those are BJTs. You definitely need a JFET.

 

[mic test]

OK, thanks

 

[cello4u]

Decided to not wait on directions and loaded up the KSA 1.1 board. Still unclear on the Biasing, but it appears to be a mic. This was my fifth try.

 

[Khron]

Still unclear on the Biasing

Same as every other U87 clone.

Apply 1kHz signal between "Cal" and ground, monitor the output signal on an oscilloscope and/or spectrum analyzer, turn bias for minimum distortion / harmonics, increase input signal, rinse & repeat.