whoaudio.... There is the "coolaudio" class D portfolio that was bought from Intersil, and some other "coolaudio" hifi-install business(?) that seems to have gone away. The "coolaudio" semiconductors definitely walks, quacks, and smells like it's part of grandmaster B-duck's empire, but they don't make any connection in writing that I see.
Only paper connection I see is a common trademark registry/claim (coolaudio and behringer both in Red Chip portfolio of names).
The terms on the coolaudio semiconductor site reads like a pirate's mantra.. Like you're on your own if there's any IP claims on the parts (we don't say where they came from) we sold you. They claim rights to name coolaudio, in the name of whoever owns the rights to coolaudio... ??? I paraphrase but it's not far off. Some lawyer must have got a good laugh out of writing that poop.
Agreed parts are old soldiers. BBD technology was originally Phillips licensed to Matsushita, but that was in '70s. Early dbx vca stuff probably expired IP too. In China one can only imagine how much of that kind of activity is/was going on, before IP expired.
If they published a data sheet on the low noise PNP we could probably identify it. I wouldn't mind if they bring back the 2SB737.
JR
I didn't bother to whois on the coolaudio semi site, that might reveal a connection but isn't definitive if it doesn't.