Thanks for that link - the speculation re a DAC in the adapter was correct. Thats a $29 adapter ....
Speakers and audio docks: I tested both adapters with a range of dock-cradle speakers and audio-focused standalone docks using the iPhone 5 and the latest iPod touch and nano models. For playing audio, the adapters worked perfectly with every speaker dock and audio dock I tested, both old and new. This includes newer speakers and audio docks that grab your player’s digital-audio (specifically, USB-audio) output and then use a digital-to-analog converter (DAC) in the speaker or dock itself to produce an analog signal.
But the adapters also work with speakers and docks—generally older models—that require an analog-audio signal. These speakers connect to dedicated analog-audio pins in the 30-pin connector, relying on the iPhone or iPod to handle the digital-to-analog conversion. The challenge here is that the Lightning connector doesn’t offer analog-audio pins—the new connector is all digital.
The solution (and likely part of the reason that Apple’s adapters aren’t cheap) is an actual DAC built into each adapter. In other words, the adapter is converting the iPhone or iPod’s digital-audio output to an analog signal and then sending that analog signal to the appropriate pins in the 30-pin connector. As an example, thanks to Apple’s adapters, I was able to use the latest iPhone and iPods with Logitech’s mm50 speaker system, an old favorite from 2005.