Hope this is OK to re-raise, but thanks to
FrankWza
and the USB > Optical suggestion, as a new PS5 owner I went down a bit of a rabbit hole on this.
I see the Signstek and Reiyin are often mentioned as USB to Optical adapters but are difficult to get in the UK. The PCM2704 DAC boards I believe they are based on are readily available for around £10-15. However from what
I've seen are impacted by the 50% max volume limit on USB ports.
So as I currently have two DAC/AMPs I tried my SoundBlasterX G6 in USB mode first and it doesn’t sound good particularly with my Beyer DT 770’s 250 Ohms (stereo, all SBX off). I have to run it with hi gain on, but even then it lacks ‘oomph’ and sounds flat. So I tried it as the bridge to my Fiio K5 Pro: PS5 > USB > G6 > Optical > K5 Pro. This is definitely better albeit the volume and gain switch has to be increased much, much higher than I normally would. I wonder if lower impedance headphones may be better suited, although I forgot to try my AKG K361s.
From what I’ve read some UAC1 DAC/AMPS; Qudelix-5K, JDS Atom DAC and (possibly) the Schiit Hel 2 apparently don’t suffer from this volume limit or offer the ability to override the host volume. I don’t own any of these unfortunately. However I read that the cheap Creative Play! 4 DAC has an updated firmware with a volume fix applied specifically for PS5 but given it’s really meant for other uses and a cheap DAC-only isn’t ideal.
So it feels like the USB to Optical adapters are set-up dependent or a workaround. I’m fortunate to still have a set of Wireless PS Platinum's around which are much more convenient, but I also wish Sony offered 3D Audio over HDMI as Microsoft do on their consoles.