I hate to tell you this but I do not believe there exists such thing. You could probably buy an HDMI-to-A/V converter with HDMI output pass-through but that’ll probably only give you regular stereo audio, knowing that stereo is a two-channel audio format. Most vintage audio electronics before the 1980s, in fact, could only provide either regular stereo or plain mono connections. Funny, my old 1994 Magnavox/Philips analog TV set has regular stereo audio speakers/inputs, along with an audio volume leveler feature, and my old 1991 Sharp VCR is HiFi stereo with a bar-graph audio level VU meter on the VFD display.
~ Jordan
I’m into videotapes and old electronics stuff, including extenders, converters and analog 4:3 TV sets (which are obsolete these days), and Miss Bianca is my favorite character in Disney’s The Rescuers (1977) and its sequel, The Rescuers Down Under (1990). I am not a Roku employee, only a user like you. ~ Jordan
Roku Express+ 3910X