That sounds like an ALPS Blue Beauty. Very nice pots. I use them on tube mixers where the customer wants rotary fadersHi Ian!
Not for fade out, just adjusting the mix output level going back to the DAW. I have seen a picture inside an SPL Mixdream XP, and it is a high quality big square blue pot...perhaps an alps.. In my case i use a 12mm 10k linear alpha 5% dual pot.
Yes, you can get some detented pots but they are hard to come by.Another solution would be to use "stepped" linear potentiometers, like those used in the dbx 266XL compressor. Every time you rotate it, you get a small click. It makes recall settings easier. I don't know where to find these ones, but they are bigger in size: 20mm diammeter...