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Comment by TruthSHIFT | Hacker News Reader

I'm glad you're having a good experience with the new MBP.

However, I wouldn't plug a $.70 adapter into a $3000 computer. Maybe you should splurge and spend $10 on the Apple adapter.

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This is one of those cases where it's good to know a bit of electrical engineering.

If an adapter, connector, cable, etc. is both "passive" (i.e. isn't doing anything clever in there with ICs that consume some of the power sent along the line) and "digital" (i.e. has transmission semantics which moot RF interference as long as the cable is within a proscribed length and between powered switches) then it doesn't matter whether you pay $0.70 or $70 for it. For example, an HDMI cable is an HDMI cable is an HDMI cable.

If an adapter/cable/etc. is "digital" but "active"—like, for example, a USB-C to Thunderbolt adapter—then it might do the wrong thing, which in extreme cases (e.g. the https://www.usbkill.com) can damage your devices. But, most data-transmission PHY layers (Ethernet, USB, FireWire, Thunderbolt, etc.) are built to protect host devices against most "dumb mistakes" that might be made by a peer device or a piece of infrastructure (and things like lightning strikes, shorted sockets, and chewed-through cables besides.) You really have to intentionally try to make a USB Killer to make a USB Killer.

Now, if (at least one end of) an adapter is analogue, then you're basically screwed and should be very scared of cheap kit. Basically, don't trust $0.70 DACs. There's a reason there's no such thing as a $0.70 USB audio or USB wi-fi receiver: these are the sort of things where the correctness of the DAC is all that stands between your computer and a huge current.

Even with passive devices, there's a risk that it's miswired and will connect things that should not be connected to each other. Most famously, earlier this year the Google engineer who reviews USB-C cables had one fry both his Chromebook and USB-PD analyzer.

http://arstechnica.com/gadgets/2016/02/google-engineer-finds...

USB-C cables aren't (exclusively) passive! USB-C cables can carry the signalling protocol for, among other things, Thunderbolt 3.1, which is an active protocol (requires powered ICs in the cables), and thus can't simply be opto-isolated by the modems on either side like a purely-passive protocol would be. A given USB-C cable might be a passive component and still be able to wreck the system it's a part of, if the system is active—that is, if the system is constrained from protecting itself against damage by simply re-defining line voltage at each medium change.

This is a compromise most people don't usually realize they're making when they favour the addition of an active "feature" to a previously-passive spec. For example, Ethernet used to be a pure-passive, easily non-ground-referenced wiring standard. But then PoE came along...

Although price can sometimes be an indicator of quality, it doesn't necessarily mean quality. I think this is especially true when the alternative higher priced product has a lot of "Brand Value" that can be attributed to the higher price.

Since cheap USB-C cables and chargers are known for destroying laptops [1] I would heed the parent's advice.

[1] https://news.ycombinator.com/item?id=11021665

In the case of Apple-branded adapters, it has been demonstrated time and again that they actually put some thought into their adapters so that your device or house do not catch on fire. Not so much with the $0.70 ones. Maybe, likely not, but hey, you saved $9.70 that you can apply to your home owners insurance premium!

Are there any Apple brand adaptors available for $10.40?

I was going to edit my original comment, but then your subtle catch wouldn't be nearly as humorous. I'll leave it there as a monument to my lack of skill in ad hoc math.

This is where Apple really confuse me…

They obviously put lots of thought into their adapters but everyone fails where the cable enters the charger - I'm about to buy my third in just over three years and the cable on my daughter's actually melted through where it shorted inside.

Why could they never be bothered to address this well know issue give them thought they put in?

You'd be appalled at what gets sold online as acceptable adapters and chargers.

Nah. USB-C to USB3.0-A is trivial. It's just a simple electrical connection, without any signalling logic (correct me if I'm wrong).

Also, I like that it's just a conversion plug versus a cable: https://www.aliexpress.com/item/LAIXI-USB-Type-C-Adapter-Mal...

Just because it's trivial doesn't mean someone can't screw it up and destroy your computer: http://arstechnica.com/gadgets/2016/02/google-engineer-finds...

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