Just after a bit of advice, I’ve just bought a second hand GT king pro and without checking the connections have noticed it doesn’t have an optical spidf to enable me to connect to my old yamaha amp. Does anyone know if it will pass through 5.1 via the 3.5mm jack on the back.
You won’t get a 5.1 output on a jack like that. It will have a stereo output. Your best bet for feeding the amp would be a HDMI to toslink or coaxial converter. You can pick these up easily online from Amazon, eBay or Aliexpress. A model is linked below: