"Anyone know where I can get a vintage ALPS 50KXA2 pot with concentric splined shafts? ("
There are heaps of Alps knock offs on eBay. You may need to be creative with search terms. Another tactic is to identify something that uses the same pots you can get cheap and harvest what you need. It's not such an odd part that you won't be able to find a replacement.
Biting the hand that feeds IT
