Well, this one really surprised me.
To be honest, it’s pretty hard on the CPU — probably because I’m not on an M1 machine. I can’t render with more than 2x oversampling, and even with oversampling turned off, I can only run one instance of the plugin in a project.
(For comparison, I can run 30+ instances of the Pro Tools stock DYN compressor with side-chain activated, but only one instance of this plugin — even without using external side-chain.)
But... what it does to the sound — even with no compression applied — is remarkable, in my opinion.
https://digital.undertoneaudio.com/products/uta-d-unfairchild-670m-mkii-v1-0
And here are a couple of videos about it from the well-known Snake Oil review channel:
https://www.youtube.com/watch?v=mWHPGId7B_A
https://www.youtube.com/watch?v=t0R8MdKU7Ls
A bonus from me for the squad:
How to build a Helmholtz Resonator DIY
https://www.youtube.com/watch?v=JUsyeBkNVEI&t=89s