Surmounting Toslink Trouble: Finally A Switch That's Reliable

Maybe I’m going prematurely senile. Or maybe EDN and Google’s search engines are failing me…along with a content search of my blog post archive via Windows. Nah…probably senile…

I could have sworn that a while back, I complained about the pestilence that is the mechanical optical S/PDIF (i.e. Toslink) switch, in the context of a writeup extolling any of you looking for a project opportunity to consider designing a more robust alternative. If I didn’t, I should have. Because these things are a royal pain in the rump:

Three digital audio inputs, one output. Inside, if you take one apart (hmmm…maybe I’ll do a Prying Eyes showcase…), all you’ll find is a length of optical fiber extending from the output through the click-rotating ‘wheel’, and on the other end ‘mating’ with one of three input cables. The ‘connection’ is proximity-based, nothing more elaborate than that, with air space in-between which the laser light needs to bridge. And if the alignment between input and output cables is at all out of alignment or if the two cables are too far apart…say goodbye to your digital audio stream.

I’ve been using these unreliable monstrosities for a while now, because both my Pioneer-developed Xbox 360 audio system:

and my JVC A/V receiver:

both only offer one optical S/PDIF input. Sometimes, a mechanical switch will fail to work right out of the box. Sometimes, it will die after a few uses. Sometimes, for a given system, it will work with one input but not another. And sometimes, it’ll work with one system but not with the other, presumably due to varying system-to-system input light sensitivity coupled with attenuation through the switch path. Bottom line: I’ve never had a switch last for more than a year or so. And I don’t want to think about, far from confess to you, how many switches I’ve gone through. Thank goodness they’re inexpensive. But they’re a good case study of the ‘you get what you pay for’ mantra.

Enough is enough, I finally decided the other day. There had to be a better way to solve my problem. And I’ve found it, in the form of Audio Authority’s 1177A:

Let’s get the qualifiers out of the way first. This device is at least 10x the price of a mechanical switch, maybe more. Yes, it costs more than I paid for my A/V receiver. Plus, unlike a mechanical switch, it will (slightly) impact your monthly electric bill. But…

• It has four input pairs, not three inputs
• Each input can be optical S/PDIF or coaxial S/PDIF; the 1177A will switch between any input suite combination
• Simultaneous optical and coaxial S/PDIF outputs are also offered.
• The 1177A can optionally auto-select an input, although I’m using it in manual-select mode because my Apple TV and Roku Digital Video Player have perpetually-on optical S/PDIF outputs that understandably tend to confuse it.
• It’s eminently reliable, because it does all switching in an electrical fashion, i.e. it converts optical S/PDIF inputs into coaxial equivalents, switches among them, then runs the output through a coaxial-to-Toslink converter.
• And hey, it’s made in the U.S.A!

Kudos to Audio Authority for identifying and plugging a previously unmet market need. Admittedly, such a product doesn’t make much fiscal sense for low-end audio enthusiasts, because nowadays you can buy an entire entry-level A/V receiver with multiple optical S/PDIF inputs for about the same price as the 1177A. But if you’ve got gear you’re happy with (especially high-end gear) save for its insufficient digital audio input allotment, the 1177A is a convenient way to extend its usable life. And hey, if you’re willing to go with the prior-generation 1177 instead, one recently sold on Ebay for $0.99…