Apple's Lightning Headphone Adapter: Analog or Digital?

September 23rd, 2016
By: Carlin "Rick" Smith

I thought this was a interesting blog article by Tyll Hertzen published over at Inner Fideltiy.  

A brief excerpt below:

Anybody in a betting mood?

Back in June 2014 I reported on a little confusion that never seemed to be cleared up. The question is, "Can the Lightning port transport analog audio?" Most sources say no. But is that true?

Now that the new iPhone7 headphone adapter is out in the wild, tear-downs are starting...I'm sure we'll be seeing more soon. The first one pointed to in a 9TO5MAC article claims this Vietnamese adapter teardown shows the adapter has a DAC chip. Okay so far.

Then this German article (translated link) claims the adapter isn't as good as the headphone jack on the iPhone6 pointing to a loss of dynamic range. This Redit poster thinks it's all a bit silly. However, the article includes this (Google translated) tid-bit.

In the measurements, it was irrelevant whether the adapter to the iPhone 7, 7 Plus or iPhone 6S was attached: The results agree to the decimal. Strikingly, however, was that the adapter on iPad delivers significantly better result list than the iPhone. This may indicate that in the adapter no separate D / A converter is seated, but the audio signal is already transmitted in analog form via the Lightning jack. Since the Lightning chips with their remote site in iPhone / iPad can each negotiate in the cable, which is transmitted, that would be quite possible. As long as Apple is silent on the subject, can only bring further tests certainty here.

The article published this table of measurements (here translated):

Read the whole article at http://www.innerfidelity.com/content/apples-lightning-headphone-adapter-analog-or-digital#9xHS30uzsadxU3Hr.99