This is a 4HP Eurorack expander module for the project found here:

https://www.pcbway.com/project/shareproject/Eurorack_SEM_style_Attenuverter_09b3e8ee.html

OK, why use this add-on? The SEM attenuator from the project above has 2x outputs of the same polarity.

This project adds additional inverted audio outputs with adjustable attenuation and bipolar offset; it also includes an 3.5mm input for mixing. It accommodates 2 attenuverters.

The project could also be used free-standing to invert any audio and control voltage signal between about +/- 10V P/P.

You can read more about this Eurorack compliant skiff module the blog post here:

http://audiodiwhy.blogspot.com/2022/11/attenuator-expander-adding-diwhy.html

Here is the blog post for the original attenuverter that drives this module:

https://audiodiwhy.blogspot.com/2022/10/euro-sem-style-attenuverter.html

NOTE: The project consists of 2 PCBs: a main board, and a front panel. So you will need to fabricate 2x boards for this project. I recommend getting the front panel fabricated in black with white silks.