Someone please explain the logic of upgrades


I just left a site explaining the improvements that can be achieved with the Audible Illusions preamp (which I happen to own) by upgrading any or all of the following:
- power supply
- signal coupling capacitors
- hookup wire
- potentiometers
- OFC RCA chasis jacks
- signal path resistors
- tubes

Now one of two things is true - either the parts upgrades improve the sound of the component or they don't improve the sound. If the former is true, then I have to ask - why didn't the manufacturer make these same upgrades and produce a class A component in lieu of a class B component? Yes, I know that the cost of the upgraded parts has to be passed on to the consumer, but I bet most of us would readily pay that extra cost to get a tricked out unit. The same applies to power cords and feet. So, why are so many "audiophile" components sold with minimalist cords and feet? If the situation is the latter (better grade parts have no impact on the sound of the unit), then shops that specialize in upgrades are practicing junk science. So what is it?
rockyboy
I was drafting up a lengthy response rejecting your learned opinions and opining that manufacturers should use only the highest quality parts, thus eliminating the need for any future upgrades. But, I suddenly realized that, had AI done that, I probably couldn't have afforded their preamp on my meager budget. So I'll drop the issue.

Bigtee - what's tube rolling?

Tube rolling is simply trying different brands of tubes to change the sound from the tubes that came with the gear.
Hate to go here - but if there are better tubes out there (and the consensus seems to be that there are), why doesn't AI sell them or at least recommend them - especially if they'll improve the sound of their gear? Don't they want their preamp to outperform the competition?. The better tubes on the market are not that much more expensive than the tubes that AI sells.
You'll almost never get the "best" tube with a new piece of gear. In many cases the best sounding tube for a particular piece of gear is a tube that has not been manufactured for 50 to 70 years. In many cases it is a major search (months to a year) to find enough tubes in excellent condition to fill just one or two amps or preamps; and the tubes could sell for anywhere from $100 to $500 each because they are rare and not coming back.

Each unit someone makes and sells needs to sound the same, or who would trust to buy it. So a manufaturer needs to find a large, inexpensive, reliable and readily available supply of tubes in order to meet demand for its products.

If some hobbiest wants to take the time to search the world for a hand-full of tubes to change the sound of the gear, then more power to them.

Audio makers don't recommend other tubes for legal reasons. If you play around with your gear and the tubes and screw things up, or blow up the unit, burn down your house, they could be held legally responsible for recommending you try it. That is why every owners manual says that there are no user serviceable parts inside; not to open the top; and return it to an authorized technician for repair.
I have studied mods that involve about $30 worth of parts that allegedly make a unit, in this case a CDP, that make it comparable to a unit costing thousands. One must wonder why the manufacture does not do. It would probably cost them no more than $20.

I guess the same logic applies as stated above.