Weak TOSLINK (S/PDIF) output on recent MacBook Pros

I have been using a surround receiver with a 10m optical TOSLINK cable and a 2006 model MacBook Pro without any problems for years. With my early 2011 17" MacBook Pro however, as well as someone else's 13" MacBook Pro from the same era, the receiver started producing frequent bleeping sounds, subtle audio drop-outs, and sometimes even downright refusing to work until it was ‘rebooted’.

I suspected all kinds of causes, including the cable or degrading components in the receiver. However, with a totally different receiver and cable of similar length, occasional drop-outs were also noticeable although this receiver was more robust and able to resume fast enough that it wasn't too jarring. After some more tests it became obvious that the light output from the new MacBook Pro is simply weaker than on older models and many other recent devices with S/PDIF outputs. This is especially visible when simply looking at the end of the cable when first plugging it into the new MacBook Pro and then one of those other devices. The photo shows the output of the MacBook Pro (top) and of a TOSLink repeater (bottom) through identical cables.
The 10m cable causes a considerable attenuation of the signal no matter what (Wikipedia mentions 10m as the limit for cable length). But with the old MacBook Pro, apparently the end result was still strong enough. The data sheet for the detectors in the receiver states that they expect at least -24dBm. My guess is that with the new MacBook Pro + the long cable, the output drops slightly below this, which is why it is just on the edge between working and not working. Some solutions are: a TOSLINK repeater to drive the long cable, a more sensitive detector with coax connection to the receiver, or a USB sound card with a stronger optical output. I settled for a repeater for which I made a USB power cable for extra convenience.
Another example where newer is not always better…

Waarom de ‘3D’ hype (weer) zal uitsterven / Why the ‘3D’ fad will die (again)

Dankzij ‘Avatar’ kreeg het letterlijk eeuwenoude principe van stereoscopische cinema een revival. Zoals bij de vorige 3D-hypes denkt iedereen weer dat alle films binnenkort in 3D zullen zijn en iedereen een 3D TV in de huiskamer zal hebben. Ik zeg van niet, en wie wil weten waarom kan de uitleg in het lang en het breed lezen (in 't Engels).

Thanks to ‘Avatar’, the ancient idea of stereoscopic cinematography experienced a strong revival. As with the previous ‘3D’ hypes, everyone is again believing that soon all films will be in 3D and everyone will have a 3D television in their living rooms. I say this won't happen. If you want to know why, check out the full article on my site.