I think this is the most fun channel strip plugin UAD offers. I’ve never worked on a hardware Vision so I can’t compare the sound or vibe, but I love tweaking on this plugin. And something about the layout attracts me like no other lover. (Or SSL channel strip.)
It is quite useful as a Unison plugin, and it’s my choice on my Apollo when I’m not using the UAD Helios.
Each module is pretty cool. The API 212L preamp, the API 550L EQ, the API 515L filters, the API 225L compressor/limiter, and the API 235L gate/expander all add some character individually.
The gain/preamp is special on this. Just tickle the red* to get distortion on the loudest peaks, a trick that helps vocals (or anything, really) cut through the mix. Plus, it sounds so vintage when you do that, even though the API Vision is a modern device. The hi- and lo-pass filters are super cool too, especially when tracking.
Be careful if you make large EQ changes, especially boosts, as the Q gets narrower the bigger you go. (But you wouldn’t be making large boosts anyway, would you?)