Thank you for that suggestion! I actually spent some time this past weekend getting a Mouser cart together for the C9 VCO. Which brings me to a question, if you (or anyone else) has time to answer it:
Item #17 on the BOM (U1) is Texas Instruments TL431BQLPR Voltage References Adjustable Precision Shunt Regulator: https://www.mouser.com/ProductDetail/595-TL431BQLPR
Unfortunately it is out of stock at Mouser and backordered for 26 weeks, with manufacturing delays reported, and Digi-Key and the other usual places I would go don’t seem to have any of them either.
While there are some components that I feel competent to identify substitutes, I’m not sure about this one. TI has other items that appear to have the same specs and I can’t for the life of me figure out what the differences are to determine whether or not they would work.
For example, this seems really similar in terms of the specifications. Maybe the size is different but I’m having trouble locating that info: https://www.mouser.com/ProductDetail/Texas-Instruments/TL431BCLPR?qs=sGAEpiMZZMuBck1X%2b7j9fKwCDSFP%2b2%2bai5XLr74JmBo%3D
Could this substitution work? Thanks for any advice!