Hello!

For my university electronics project we have to build or own analogue audio gear (a degree in Audio Engineering & Production). I don't really know a heck of a lot about circuits, altough I'm doing my best to learn from many different sources. I want to build an optical compressor, with a pre-amp with toggleable 48v phantom power. I'd like to have controllable attack and release as well as input gain, output makeup gain, and a threshold setting. Ive constructed my schematic around a few different sources which I'll list at the bottom. For now I have an unbalanced output, which I may change to an XLR, but I'm not too worried about that at the moment.

http://imgur.com/a/M3W7v1y

I'd love to know what people think of my schematic as well as things I can improve upon

THAT1580 Pre-amp:
https://thatcorp.com/wp-content/uplo..._Datasheet.pdf

Envelope Follower:
https://therepaircafe.wordpress.com/...e-ar-generator

Rectifier:
https://www.eeeguide.com/precision-full-wave-rectifier

 

Why there is no negative feedback on U2a? It will behave like a comparator, is that what you want?