Please tutor me on some integrated amp basics.

Cables aren't hard to build either. 

Monoblocks are about as far from an integrated as you can get. They're individual amplifiers for each channel. One amp per speaker. The advantage is the least possible interaction between the channels. It's also the most expensive, space consuming option. A good compromise is a dual-mono amp which is basically two monoblocks in the same box. I'm not sure if anybody builds integrated amps like that. 
I'm a class A man myself. Generally class A amps sound and perform better. I'm not a fan of class D. Class A and AB simply add gain to an analog signal. A class D amps reduces an analog signal to high frequency garbage, amplifies the garbage, and then tries to reassemble music from the garbage with very complicated filters. The benefit is the amps are small and very efficient. On the other hand, a 100 watts class A amp makes a good space heater turning at least 2/3rd of it's power draw into pure heat. 

Trying to explain amp classes is a little complicated, but I’ll try.

Transistors don’t just turn on as soon as you apply some sort of signal to them. It depends on the transistor, but a typical value just to turn them on is a .7V difference between the gate and source or base and collector pins. It can vary a good bit though.

That’s a problem. For the sake of discussion we’re going to talk about complimentary push-pull topology because all class AB amps are that topology. If it takes .7 volts (an arbitrary number for description sake), the trasistors aren’t going to produce any gain until that signal strength is reached. That produces what’s called crossover distortion. Crossover distortion is nonlinearity in gain as the signal swingings from positive to negative and is handed off from the transistor pushing to the transistor pulling.

The solution to crossover distortion is to bias the transistors. Biasing is putting some DC on the gate or base pins of the transistor to turn it on. This is where we get into the difference between class AB and class A. In a class AB amp the bias is just enough to turn the transistors on a little bit just to get the into their linear region and past that .7 volts where they do nothing. In a class a A amp you go much further than that. In a class A amp you bias the transistors deep into their linear region. This causes them to draw amps of current at idle instead of milliamps like in class AB. That’s why class A amps are so big and heavy. The cooling solutions need to be vastly more robust and the power supply needs to be much more muscular.

As a class AB amp amplifies a signal, one half of the amp amplifies the positive half of the signal while the other half amplifies the negative half. In a class A amp both halves of the amp are biased so high that (ideally) neither side of the push-pull ever shuts off and both sides carry the signal completely. The benefit of this is that the nonlinearity of the individual gain devices are minimized. The strengths of one transistor minimize the weaknesses of the other transistor. That’s the idea at least.

A good class AB amp with well matched parts can hold it’s own against a class A amp, but many, myself included, feel class A has superior sound.

Additionally, a push-pull class A amp can easily transition to class AB and belt out 2 or 3 times it’s rated power for headroom vastly higher than it’s nominal power rating suggests. It does so with a small distortion penalty. However, class AB has a similar distortion penalty as the signal surpasses the low bias. Typically that shows up as higher distortion at low power levels and in micro-details.

Class D is a radically different animal. In class D the devices are only turned on at super high frequencies related to the instantaneous demands of the signal. The output signal is nothing more than very high frequency pulses in proportion to the input signal. The output then needs to be extensively filtered to turn it back into a linear waveform without the high frequency noise produced by the constant switching of the gain devices. Opinions on class D are world’s apart. Some hate it. Some love it. Ultimately, the gold standard class D is being judged by is class A, and I don’t think anybody disagrees with class A being the ideal class of amplification.

If you have any other questions, feel free. To get better clarity on the subject of classes I suggest Nelson Pass’s article "leaving class A" and his Burning Amp lecture "selected topics on push-pull topologies"

There are class C amps, but they're completely unsuitable for hifi. Class B is a class by itself, too. Class AB is a hybrid of class A and class B. Class B is the same sort of push-pull topology (though it can be single-ended) with no bias to turn the transistors on at all. LOTS of crossover distortion. There are applications where signal distortion isn't that big of a deal though, which is why those classes exist, but hifi audio isn't one of those. Walky-talkies and cheap transistor radios use class B.

This is the link to the "Leaving Class A" ariticle.
https://www.passdiy.com/project/articles/leaving-class-a

This is the link to the Burning Amp lecture
https://www.youtube.com/watch?v=MBmDi-4zdQk&t=2s

Ieales,

Sorry, but class A is most definitely the ideal form of audio amplification. It's not the ideal green technology. Two totally different and completely unrelated subjects. The best a class AB or class D can hope to sonically measure up to is the quality of class A amplification. I don't know who you buy class A amps from, but reliability is rarely an issue. 

Huh? I don't know why this dogma about gain devices persists, but that's all it is. The topology is what characterizes the sound of an amp at least as much as the gain devices, and I think even more so. The characteristics that give away what the gain devices are come from the compromises required to make those gain devices work and the distortion. There is no class A sound, or BJT sound. There's just the character of the distortion the topology produces. 

Na.... I don't think my F5 is the greatest amp ever. It's a very good amp that I built and tuned to suit my speakers, which are the best $4000 would buy me in my estimation. There's nothing fuzzy about the amp at all. Dialed in to it's lowest distortion it's hyper detailed and clinical, more so than any BJT amp I've ever heard. As it is, the F5 is flat out to 1,000 kHz. There are no bumps or dips to compliment the response of the Focals. 

High order distortion is what makes Focal speakers sound bright, and all speakers in general, really. And that's very characteristic of class AB amps. They almost always have a power curve that starts with high levels of high order distortion before reaching their best performance. That's one of the biggest downsides to most high power class AB amps. The low power distortion is kind of obscene and leads to brightness and a false sense of dynamics. 

In a perfect world I'd have a pair of 50 class A monoblocks with JFET outputs. Not much hope for that though. I'm happy with what I've got. Probably happier than most. Just throwing out here what makes me happy. 

ieales,

You didn't actually look at the measurements or read the article, did you? Auxinput was calling the 936's bright with a thin mid-range and here you are quoting an article that calls them extremely neutral and NOT bright while calling them very colored. I tend to agree strongly with the review. They do have a meatiness in the upper bass, but it gives them a presence and physicality most other speakers lack. The mid-range isn't at all thin, not are they bright, and neither the measurements nor analysis suggest either. 

Meh... Some like to make big mountains out of the mole hill of phase. It doesn't seem to matter all that much. 

ieales,

Some of the first real HiFi speakers I heard in a store were Theils back in the day when phase alignment was the new holy grail and even B&W was giving it a go. Meh... Big deal....

I’m a real whore for great imaging. Clearly absolute time alignment isn’t a requirement if Focals do it as well as they do. The measurements you see in the rags don't really tell the whole story. Like with my 936's. JA measures them on tweeter axis. Who's sitting with their ears 42 inches high? Nobody. At 36" it's a different story. 

Ha! You've never tried lifting a Pass XA100.8! 

I'm not sure about the 500 hours number. My Focals didn't seem to reach their full potential for most of a year, whatever that pans out to. I'd just stream any old thing on them as soon as I got home from work for weeks after I got them. 

Skyscraper,

If you ever want a pair of 100 watt F5 monoblocks I can build you a pair for about $4000 or a fully dual mono 50 watts amp for $2000, let me know. That’s basically what it costs to build them. 

@geoffkait 

What's your point? Who can't buy reels of cryo'd cable and wire? I can. I don't think it makes any difference. Anybody needs any, let me know. My friend's stuff sounds great in my amp. 

Skyscraper,

You’re putting together a rig nicer than one I’m likely to own anytime soon, but if I had your means I wouldn’t succumb to pressure to blindly grope at cable solutions. Be analyitcal about it and buy with the conviction that sold you on the speakers. Just get some real basic cables and listen to them very carefully, at least until you’re sure the speakers are broken in and expressing themselves as they will for the rest of their lives. Then try something different, but still cheap. Understand how they’re built and what those features and designs are doing. Google and read about cables, how they’re built, and how they measure. Try to figure out what different measurement characteristics translate into design-wise and sound-wise. Then if you decide to blow a couple grand on some cables you’ll have a much better idea of what direction to look in. Guesswork is hardly a solution.

Inside my F5 are two pairs of small signal input wires. They’re 6 inches long. I originally built it using some nice, shielded IC cable. It was hard  to work with. I replaced them with some 24g solid conductor twisted tweeter cabinet wire. Real simple stuff. It sounds noticably better. The wire makes a difference, but I don’t recommend going whole hog before you know what you want to improve in a broken in system.

I'm not the guy to be dishing out great cable advice. I make my own. The ones I'm using are a rip off of an idea of a popular cable that uses 4 conductors braided together. Mine are 6 16g conductors, round braided and covered in cloth, terminated in gold with silver solder, and equal about 11.5g combined with much better skin effect and lower inductance.