Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems HD621 Does it support 4K?

I am using a new 4K / UHD Roku 4 with HDMI out and am not getting sound or picture when I hook up to the 861 via the HD621. Therefore, I am going directly to TV and then using optical out on TV to 861. What am I doing wrong. Would a HD Fury help?