pauls,
found Zhaolu pics - it has a standard Toslink optical in (the same as on CD, DVD players). So if source is one of them, Toslink plug-Toslink plug cable is required. If source is for example MP3 player (iRiver H1XX) cable should be Toslink Plug-Toslink 3.5mm plug. Examples of both can be found on Selby Acoustic page under Audio/Digital cables, or in Jaycar catalogue WQ7260, WQ7264. The US based mob at
http://www.sysconcept.ca/product_inf...roducts_id=254 have pretty good stuff.
There is lots of optical cables out there, ranging from few bucks a meter into hundreds of dollars.
The light travels from source to receiver in means of literally bouncing off the wall of optical fibre. Therefore the physical properties of fibre material, is purity, refraction index and the length of path that photons travel will determine the quality and integrity of signal. The best cables are made from optical grade glass, encased in teflon or other exotic multilayered jackets. These cost arm&leg and would be an overkill for this application. Perhaps an analogy would be using solid gold cable as interconnect between DAC and source. Most common are fiber made from polymer, surfaces are either polished or not (polished are always advertised by manufacturer, adds considerable cost to manufacturing process). Purity of polymer is a driving cost vs quality factor here. Good quality polymers have really low loss (in dB) per meter and actual termination into connector is very important as well.
Knowing all that I would personally go for polished plastic, with some decent outside diameter insulation for mechanical protection, terminated in metal connector, preferrably with spring loaded tip. Shorter here is better, no need to have unused length of cable coiled, but also no need to try to save every possible inch - up o 3m should be no problem. These can be had for around $50 on Selby's (e.g. Neotech brand). Or for $110 there is 1m long Reference Optical Lead Qunex OT/1 (
www.rsaustralia.com, stock No. 358-0672) that should satisfy even the most demanding customer here. This one can be paired with Toslink Female to Optical 3.5mm Male Adaptor (Jaycar PA-3575, $5.50) to use it as a single lead for either CD/DVD or iRiver(+adaptor) sources.
And last, but perhaps most important thing: keep every optical suface CLEAN!
That goes for female Toslinks on your equipment as well. No rocket science here, even pros use high grade (70-99%) isopropanol with fine brush but it is important to imediatelly blow it with blast of clean compressed air (max 10psi). Dicky's Smith aerosol does the job.
I did measure optical power loss on multichannel bus by slightly touching polished end with my (allegedly) clean finger. Power on that channel dropped by 7.5dB
(and considering that 3 dB loss means half power) - enough to make make paranoid about cleanliness of optical gear. Checked it with video probe and microscope - not a pretty sight.
Hope this won't be taken as a lecture but as a help to fellow hobbyists.
Cheers,
Lad
