Are manufacturer AC cables good enough?

This is not what double insulated means. Double insulated means that no single failure point can result in dangerous voltages (with or without equipment grounding). That could be two layers of insulation or reinforced insulation.


The ground connection can also be a critical part of an EMI reduction strategy.

"Double-insulated" simply means anything the user would be likely to touch is made of non-conductive material. In 120V code-compliant electrical systems, the neutral conductor is also connected to ground, and thus, to the circuit breaker.

When a builder stakes his reputation on his design, he will use a good cable.  When a product is subcontracted out, NO!  Jame Bongiorno, of GAS/Ampzilla fame,  was supposed to be a great designer, but compared to similar Julius Siksnius designed and built Audire equipment, it was junk.  The difference:  James had his stuff made by bidders; Julius built his own factory..

That would certainly explain Julius Siksnius’ great fame. 🤗

Since there is no evidence, none at all, (not a sausage, not even the smell of pork - plenty of snake oil aroma if you like) that expensive power cables do anything that the manufacturer supplier ones can’t, it’s time to bring out the Hitchens Razor.

“That which can be asserted without evidence, can be dismissed without evidence.” – Christopher Hitchens.

Take a look at what Gene at the excellent Audioholics site has to say on the matter.

https://youtu.be/7YIGLnbc12I

cd318

Since there is no evidence, none at all, (not a sausage, not even the smell of pork - plenty of snake oil aroma if you like) that expensive power cables do anything that the manufacturer supplier ones can’t, it’s time to ...

There is abundant evidence that "expensive power cables" can make a difference - a virtual mountain of it! There are countless testimonials in print, online and in real life from users that have first-hand experience. Indeed, premium power cables are a distinct niche within the audio and audio cable industries.

Of course, much of the abundant evidence isn’t the kind of evidence you seem to prefer, which is fine. But to pretend that "there is no evidence" is really disingenuous.