Hello does anybody have the Push button filter circuit kit from microphone parts schematic or booklet

[Papa Tango Charly]

Hello everyone!!! I have few microphones Avantone C46, Tbone SC400, Apex 435. I have bought them thinking i could
Mod them with the push button filter circuit kit and the V57 circuit from Microphone parts, But they don't sell this kit anymore.
Does anybody have the schematic or the booklet for the push button filter circuit kit Avantone C46, Tbone SC400, Apex 435 etc...Thank you all! i don't want to waist these circuit!

 

[Khron]

It's probably identical to the sE X1, i'd reckon?

https://khronscave.blogspot.com/2017/05/se-electronics-se-x1-rebuild.html?m=1

 

[Papa Tango Charly]

Thank you very much! i'm going to check this out. I'm looking foward finding mods that improve cheap microphones.