Firewire to S/PDIF?

[elfergos]

I have a Bayerdynamics headzone 5.1 headphone surround sound system that I would like to use with more of my equipment, PS3, TV etc, it only has a firewire digital input. What is the most effect way to get from firewire to S/PDIF without breaking the bank?

 

[elfergos]

Alternatively, I see a lot of cheap spdif to 5.1 analog converters such as these: http://www.amazon.co.uk/gp/product/B00AZHNXNO/ref=s9_simh_gw_p147_d0_i1?pf_rd_m=A3P5ROKL5A1OLE&pf_rd_s=center-2&pf_rd_r=1Y0CP76DAR4345WBFJJZ&pf_rd_t=101&pf_rd_p=455333147&pf_rd_i=468294

but the reviews tend to be a bit all over the place with complaints of poor volume and interferance, anyone know of a reliable higher market alternative that is recommended?