AC/DC and DC/DC are way over 90% for the whole conversion from input AC voltage to output DC voltage. The actual AC/DC step is 98%+ efficient.

Just converting the AC to DC, the efficiency is higher the higher the voltage, using a simple diode bridge rectifier. You lose about a volt from the diodes. And now you have pulsed DC. If you use a capacitor to smooth that out, there is little loss. But actually there will be a high frequency switch-mode flyback converter that will take the pulsed DC and convert it to the load voltage with low ripple. This will be way over 90% for any fixed application where you know the input and output voltages at design time. If you need input below ~ 85V then efficiency will be lower. Car battery chargers will always have a known load voltage, so the efficiency will be high.

OTOH converting the 6V AC output of a bicycle bottle generator to AC, the efficiency drops to about 80% because of the fixed voltage drop of the diodes. And if you pedal slowly and that generator only puts out 4V, you're down under 75%, depending on the diodes.

Keep in mind that the "directional" cables are grounded at only one end, and you can't guarantee that digital and analog will have separate ground paths. They won't be separate, actually. So the noise from the digital system really does leak into the analog side. Most of that can be filtered out, but it isn't always easy to filter it just enough but not too much, in varying conditions that are only partially under control of the sound team.

For home use, perfect filtering should be easy, and problems are limited to start with. But in pro audio this shit matters. It is not a pure digital system.

I'm not sure about other systems, but most modern linux burners can set the flag. You can also flag them as audio masters, which is really useful for when you want to stick them into pro audio equipment.

IME if you set the flags right you can even get them to play in drives that attempt not to play any kind of CD-R. :)

If you just snootily turn your nose up, though, you could fail to realize that there was a difference, just not the obvious one that you thought and that sounded wrong. If you keep trying until you find a plausible difference, then you're ready to understand that when the CD-Rs are tested, there are some number of units that almost pass the test, but have a higher likelihood of data loss. These can be sold as audio CDs, because audio data is more tolerant of data errors than computer software, or even other media types.

It is important to know the difference, because if you see the "audio CD" on sale for cheaper than the "data" CD, it might not actually be a good buy. Unless your use case is digital audio, then it might be worth the increased risk of a bad bit or two.

If you wonder if ground loops might be a bogus concern, you've never worked in pro audio. ;)

Ask anybody working on the stage before or after a concert. They can set you straight on this one.

Actually, in pro audio ethernet is used with proprietary protocols, handled by black box ASIC chips with special switches. I deal with this crap in the studio. Where I am they use it mostly for the personal mixers providing monitor outputs, but some places use it for inputs too.

Also, warning for those about to embarrass themselves making fun of "directional" cables, that means it is grounded at one end, and you put all the grounded ends in to the same device to avoid ground loops. If you don't know what it is, it must be brain-numbingly stupid... right? Ignorance is bliss.

We use normal cables, sure. But we do buy expensive ones with nice plug shielding, because musicians may or may not even be sober at work. Expensive cables isn't just for fancy looks, that build quality can make a real difference. Plus, it might be a lot easier to get the bean counters to agree to buy premium cables, than to get them to agree to replace equipment. They might tell you, "use the spares until they fail" in which case you'll regret not having spent their money on the "over"-priced ones.

Same with instrument cables. No, a brand new expensive guitar cable does not sound better than a cheap one. But after 300 shows, the cheap one craps out during a show or session, and the expensive "hifi" one didn't because it has premium long life rubber and better plug strength. So it does actually sound better once you factor in the way it sounds when equipment fails and you can't even hear the instrument. Most of that benefit is in the middle price range, of course. A $1000 guitar cord probably has metal mesh "shielding" that substantially increases cable strength, but the $300 one already has plastic mesh that will provide more than enough abrasion protection.

Also... some commenters don't know this, apparently, but a "placebo effect" is a real effect. It doesn't mean it is a scam, it means the people were successfully tricked into getting healthier faster, or in this case, to have more fun. If you "trick" them into thinking the artist is more artsy, they might enjoy it more too. Pretty snooty to claim they're not really enjoying the subjective aspect of their choices as much as they claim to... especially if you're also claiming that due to the placebo effect they really are enjoying it more!

It isn't ludicrous at all, for the exact reasons you explain at the start. It is simply guaranteed to fail. But asking and being told no, that is part of the process.

I personally hope that people keep asking.

Most cities in high density urban neighborhoods already provide charging stations at metered parking spots, and the parking time limit is only business hours. Also most urban municipality-owned parking garages have charging stations.

Those urban libraaals are already building this stuff and living in the future. Even in small cities.

Most of driving is to get out of town, often up in the mountains way off the beaten path... I can't imagine needing more than 250 miles range. A fast charge just means I'd need a 30 minute meal break every 250 miles. For people who aren't professional drivers, that's a good idea anyways. But it is very unlikely I would go that far and not fly.

We are only a handful of years away from $6k EVs with 250 miles range. The future is coming. And those cars will be the dinosaurs of the self-driving age because they'll never lose the ability to home fuel.

What they need is to set it up like a carnival ride; a car elevator takes it up and puts it into a slot in a vertical machine. This is great for high traffic areas like tourist traps, where land space is expensive. Then you're out of the car, waiting in a boring lobby with a loud television, next to the convenience store/gift shop with soothing thematic music.

This is why (if it wasn't for the TSA) flying is so much more convenient.

That's why we turned the lottery over to the State, and turned it into a Stupid Tax to support education.

My State did that with alcohol distribution, too. Organized crime can't penetrate the distribution layer that way. Too many bar codes and computerized inventory systems.

We threatened the cinemas with a law requiring them to allow customers to bring their own bottled water, and the companies all decided to agree to allow it without the law. But they just don't earn enough of the movie pie to be more important than soccer moms, so we can have water again.

No thanks. I'll watch at home.

Looking at current installs and technology, I think that fast charging will be most of the mobile charging, and slow charging is what you do at night to top it up and preserve battery life.

Fast charging is not inherently expensive, and patents don't last forever. Price differentiation will shrink in the future for charger tech.

Yep. There is a gas station by the freeway where I can buy gas for 10 cents cheaper than anywhere else. I went there two times. Both times it was such a hassle, I don't even stop there when I'm going that way. I shop at the 2nd cheapest place, which thankfully has "traditional" service.

I don't blame them for wanting me to go into their store. But that said, I'm not going back.

It may turn out that shared cars are better-maintained than average, and get repainted regularly (and cheaply, done in-house by the company)

Also, truck rentals are a thing. And, the company knows who the last user was; if they left it unclean, they'll get a $300 fee and either not do it again, or get banned.

The funny part is that this is already a thing. Having a dinner date is one of the prime reasons these car-less young men are renting a car a couple times a week. A lunch date, they bicycle together.

I live near downtown, and lots of these cars get parked on my street. Probably 15% of the people I see waving a credit card at the windshield are carrying flowers! And over 50% looked "dressed up." (eg, nice clothes of a style more mainstream than the person's hair)