What has made Class D amps better?

Load of rubbish, I've had the LYD's nearly six years and they're still going strong, Ragan had them before me I believe. I know someone who bought Geithain's with their RL Class D and they've had theirs well over a decade. Klaus Heinz (HEDD / ADAM) has stated on more than one occasion that a modern class D amp can go toe to toe with a Class A nowaday's..

Besides some very early oopsies I've yet to see any technical evidence that a modern class D is actually worse. Although I'm always happy to learn something new so bring on the scientific examples.

Yep, as Eric said and here's a good technical piece on the up's / down's and reasons why a Class D can cause issues.

www.audioholics.com/audio-amplifier/amplifier-classes

As always, it's about design and money.

I actually read that right before I posted this! Super helpful in understanding how the different types work.

I know Dan has an axe to grind on Class D..  I'm trying to be civil here but it's absolutely false about gate degradation, etc.  Class D amps are technically the same thing as a half-bridge motor controllers and they are used in millions of products for decades and decades now (I should know, I designed them for a few years).  The pitfalls are known to a point where simple rules of thumb are used by most.  There are ZERO engineers designing PWM controllers to fail.  Failures cost money for everyone.  I deal with it every day in the design world.  There's some kind of universal belief that bean-counters rule the engineering world (and there are definitely cost analysis done, etc) but for the most part there isn't a bunch of non-engineers dictating the parts used, even in China.  I deal with chinese production all the time and can say that even the worst production facilities are putting the part choices on the engineers simply for blame-shifting's sake.

That said, ANY capacitor taking significant pulse currents will eventually dry up and fail.  We see it in analog power supplies and we see it in SMPS power supplies.  Old tube guitar amps need recaps because they were the WORST at hard ripple currents across the caps yet we just take that as "normal" lifespan and nobody complains about it, yet it's practically identical in failure modes..

However, when a SMPS fails because the caps take the same beating, "it's crap" is the general consensus.  My take is that it's because it's a complex system that is hard to understand at a high level and even harder to understand the nuances in the details of, so folks just don't "get" it.

Some WILL die because the caps being used aren't up to the long-term task.  Most will be FINE for a decade+.   Caps are RATED for ripple and most even openly specify if they are "for SMPS" or general purpose.

The only drawback is that Class D amps tend to increase in distortion the closer you get to their saturation currents, aka; the max power output.  That's why folks tend to over-spec their class-D amps a bit so that they never reach a higher distortion level.

This is a really interesting point. I actually just had a bunch of work done on a Fender Deluxe I've owned for 25 years. Second time I've had it re-capped. Didn't think twice about it. 

But the difference is that any schmo at a decent guitar shop can get my tube amp back and running in a few days. Not the same with a capacitor in a digitally controlled near field monitor, right? 

I just thought this interesting as he has other large monitors, so I wondered if he ignored the Dyn caution and drove them loud with the extended bass ?

I don’t see a lot about dyn failures ?

You're not taking your Core 59's to Banjo Mart for a quick tune up?

Almost all.

But my 2 favorites have not umm Switched for the most part.

They technically could! The problem being the thing I described, it seems overly complicated to someone who doesn't work with them.

But with anything, time and experience can alleviate that.

Overall failures might be more complicated if more than one part fails though.