Thanks DM for progressing the discussion further. Circuit design is the holistic level that can be properly atributed for components performance and "character". An engineered product is more than the sum of its parts. There is a designer, an idea that makes it all work together at its core.
If an amplifier is consisted of 15 diodes, 32 capaciors, 1 transformer, 3 switches, 2 trimmers, 84 resistors.... etc. Take them all and randomly connect them on a breadboard with no logic applied to it.
Plug it in.
Bum!!!
Didn't work?
Not only it won't work randomly but give the same materials to two different designers and they will make 2 different amplifiers that measure differently and due to that amplify differently. Well if we gave them the same parts why did they make different amps, not the one best possible one of all the 7298450239203 random options?
Firstly knowledge and inspiration, secondly goals.
First one means a designer has a quantity and quality of knowledge that is different than other designers. He may belong to a school of thought like zero NFB Matti Otala or Nelson Pass first watt or even free amp circuit design from a1967 Wireless World magazine article. If both designers we gave parts to assemble an amp belong to the same school of ideas in engineering, they will make fairly similar performing and sounding design inspired by their favorite inovators.
The set goals is where individualism, creativity and invention comes from.
What is a the best amplifier? To one designer, lets call him the "engineer", it will be the best measuring and performing one and to the other designer, which we will call the "alchemist" it's the best sounding one to his/her ears even if it compromises performance.
The engineer will aim at least THD, most linear FR, lowest output impedance, highest slew rate and power output in a wide bandwith circuitry. To achieve this he will use a lot of parts and complex circuitry for his amplifier and to meet a budget (s)he will have to use stock parts. Finished product will weight 30kg, drive any speaker on planet earth with ease, weld your child's bicycle, warm your living space, frigidize your wife's libido, inflate your electric bill and sound dull and boring like a wire with a volume knob. The marketing materials wont be exciting as well, considering all the money went into building and delivering it.
The alchemist will use less parts in a simpler circuitry and focus on getting a certain type of sound out of it. The amp will have high gain, higher distortion, noise from the grid, high output impedance, low power rating but large PSU and the bandwith cut off at 20kHz so the underengineered circuit doesn't have to deal with more than it has to. Noise hiss has loudness effect in human hearing, makes things "pop out" when unnoticably blended in with the pure signal, This translates to a loudness curve of uncontroled and weak fruity lower bass but very gitty exciting punchy upper bass, mids and highs. A lot of the musical ambient microdetail is lost and the sound may look flat and 2D but it will be more direct, simpler to communicate in foot tapping musical entertainment. Loudness curve due to human nonlinear hearing gives an impression of an amp that is more powerfull than it actually declares. Just like pushing the loudness button on your AIWA mini system.
The finished product will weigh 7kg including the box and the 4kg of marketing brochures with exciting names with TM symbols next to them.
The engineer's goal is to build each time the bigger and better chappel for high fidelity history, humanity, the mentor, for mom to be proud and so on. The alchemist's goal is to make product that common people will like to buy and thus make coal into gold.
A lot more can be said on the topic but i shouldn't hog the mic.
Cheerio.
:wave: