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Teardown Confirms Digital-to-Analog Converter in Lightning EarPods and 3.5mm Adapter
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I wonder what process was used to make this chip? It seems a good application for 22FDX going forward.
I guess I should have put "necessarily" in italics and bold.
DACs at the chip level are relatively simple circuits. Especially for low sample rate high-resolution applications like audio. For such systems there's an incoming PCM serial digital stream representing a sampled time-varying audio signal. That gets interpolated to a higher sample rate, delta-sigma modulated, 1-bit converted to analog, and ultimately low-pass filtered and amplified, producing an analog output signal. I suspect Apple is using some variation of this architecture, possibly more complex, and likely with their own secret sauce. In any case, the DAC in die form is tiny, yields are high, and therefore the cost is low.
Filtering to remove higher frequency digital logic noise from the desired audio spectrum is part of any mixed signal system and par for the course. Fortunately there's wide spectral separation between unwanted high frequency logic noise and the audio spectrum. Good design techniques and the use of chip capacitors/resistors make that relatively easy. And cheap.
Also, in the case of Apple's DAC adapter and digital AirPods, not having the DAC and output amplifier inside the iPhone where it would be subjected to far greater digital noise and at greater amplitudes, should make filtering even easier. Yes, there's a Lightening digital interface at the input side of the adapter that can potentially induce digital noise. But those digital lines are low-level shielded differential pairs that help attenuate that potential noise source.
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If you do buy one for your 6s, maybe buy this too, to enjoy the full 7 experience.
http://appleplugs.com/
Seriously though, I did buy one for my SE out of curiosity, and the sound quality is the same. You cannot output sound from both so it won't benefit you as an audio splitter. So about the only benefit I can think of is compatibility with an iPad, or iPod Touch, so you don't have to keep pulling the adapter off to use with your iPhone. The adapter seems somewhat fragile, mainly in how tight the 3.5mm connection is. So I would be concerned about how well that end holds up over time, and take steps to minimize the number of times I had to do it.
I would have loved one of these to use back when I only had an AUX jack in my car. I got tired of plugging and unplugging two cables into my phone, so being able to plug just one cable to charge and split out my mic and aux feed would have been amazing, even if I had to buy a $40 Belkin adapter as well.
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But even I know the iPhone 7 comes with an adapter in the box so you can still use any old crappy headphones with a 3.5mm plug and I don't even own the phone.
Nothing is stopping anyone from using any headphone as far as I can see.
I'll tell you what, it sure seems like apple should have waited to remove the headphone jack after they included wireless charging. I now spend all day going between "do I charge now" or "time to listen to music or talk on the phone". Those are choices that simply didn't have to be made previously and really don't need to be with the widespread existence of wireless charging options.
I for one, has been using the Apple CCK for a very very long time (since the 6 Plus) to output digital audio signal to a FiiO E07k portable DAC+Amp to listen on my B&O H6.
So, nope, I am not being limited to listening on my expensive headphones through an adaptor with ****** DAC. Nothing has changed for me.
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Yes, and how does the quality of this adapter DAC compare to the DAC for the audio jack in earlier iPhones?
Also... for those that are audiophiles, the output amplifier can be better and better matched to your particular headphones.
Effectively the same from the early objective and subjective reviews. Minor differences most people will never notice.
On the other hand, there was nothing stopping this from happening in the past.
Of course. External DACs (with amplifiers) have been around for a long time. The point I was making is that Apple's move will accelerate adoption with better devices and more choices coming to market.
Hmmmm. Like a microphone pre-amp? I suppose it's possible Apple amplifies the mic input before it goes into the ADC. Seems a little extreme though ...
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Actually it doesn't matter what you get from a third party. Most people don't buy a pair of headphones on specs alone. They put them on their ears and ideally listen to a trusted music source and genre they will be using them with, and determine which they think sounds best.
If a third party puts a DAC which specs are inferior on paper, but the implementation sounds better than another one that has technically superior specs, the customer is most likely going to buy the one that sounds better.
This argument has been a non-starter since day one.
was interested until you said digital noise
Noise generated from digital sources is everywhere, including on the output of the 3.5mm audio jack.
The right question to ask is how far down is it in dB (and in what frequency spectrum) relative to the audio spectrum you're listening to.
No you don't. You could already use digital audio over lightning on previous iPhones. You have less options as you cannot use analog headphones without a dongle.