Hybrid FM multiplex decoder?

[stelios]

Fm doesn't appear to be dying anytime soon.
The sx 780 and sx 3700 from the 80s have excellent decoders.
Another poster here built a decoder using the chip to lock the carrier and a tube to decode it.
https://www.diyaudio.com/community/threads/build-a-fm-stereo-decoder-using-chip-and-tube.348203/

Yes, I mentioned it in a comment earlier and it's now re-opened after having requested the moderator to do so.
It's a great thread. The original poster has also created a webpage to showcase the results of this project:

https://www.wa2ise.com/radios/stereo6hs8/6hs8stereo.htm

(The website is actually huge... a lot of valve radio stuff there.)