>No worries about it being too in-depth, I'm usually more concerned with things not going in-depth enough! I get practicality and conciseness being a concern and all, but I like knowing the why's behind the what's.

Generally I agree but unless you are going to get into the design and production of vacuum tubes a good amount of the knowledge is kind of useless. The thing is tubes are far from ideal and even if you sift through 100 tubes to find those few which kind of line up with the ideal they start drifting from that ideal the second you put them to work and they all drift away from that ideal in their own way. We can compensate for this with exotic topologies but if we do that we end up designing away everything inherent to the tube sound and end up with something that costs and weighs twice as much and sounds like transistors*. The truth when it comes to the simple topologies used in successful tube amps is that the curves and a few simple equations (ohms law, parallel/series resistance/capacitance and rc filter) will get you just as close if not closer to your goals as the theory and math and do it in a fraction of the time and once you really get it all down it all turns into a few rules of thumb. But getting it all down is rather nebulous and personal, those rules of thumb are essentially cliches and seeing the wisdom of a cliche is always hard earned.

This is ultimately the genius of Leo and why Fender became the biggest name in amps, he realized that even if the math and theory said 120k was the ideal value tubes are not ideal and are not constant so 100k is close enough so make all the plate resistors in the preamp 100k unless there is a very good reason not too and exploit the economy of scale when buying resistors. Most of Leo's amps from a given era are pretty much the same, he let the speakers and cabinet give the difference in sound. Well worth spending some time analyzing his amps.

>Passive Audio Network Design is by Howard Tremaine, not Aiken.he

Yeah, that was not worded well, I was referring to Aiken listing Audiocyclopedia and not Passive Network Design. Audiocyclopedia is a great book as well but I think that one is best left for when you have a good understanding of things, it is closer to cookbook than guide but gives better explanation than most cookbooks. Passive Network Design is great and will give you all the nuances of things like tonestacks as well give you the knowledge required to build a 1940s style recording studio if you feel so inclined.

*The actual "sound" of transistors is more that those topologies which are exotic in tubes are common in transistors because doubling your transistor count only adds a couple ounces in weight if any and maybe a couple dollars. If you treat design with transistors as you do tubes you get fairly tube like in dynamics and we see this demonstrated in the rather naive 1:1 translation of tube amps to transistors that runoffgroove got big with.

Edit: when going into ideals I forgot to mention tolerances of passives, 5% for resistors and 10 or 20% is common for capacitors and these all drift away from their spec as well and capacitors start leaking DC throwing off your bias. You play the odds like Leo did and a good number of your amps actually get closer to the ideal as they age when you add in the less than ideal tubes and wear on the speaker and variations in line voltage, etc and is kind of amazing these amps work at all after a decade or two. When it comes to tubes as long as you hit the dart board you are probably good.