Dedicated line question

OP, you are thinking correctly.  In that sense, same draw as long as you don't plug anything else in.

What you are talking is not a dedicated line, which by definition is one breaker one wire one outlet. You can have multiple gangs in the outlet. But the minute you start stringing it to others it is no longer dedicated.

Party line. You want a crank with that?

No piece of audio gear requires a dedicated line! Who told you such nonsense? A preamp, power amp, streamer, DAC ... don’t draw much current. They are not stoves, refrigerators, washing machines, dryers which suck up a lot of current!

You want a dedicated line for separation and less influence of nasty equipment to your system. You also get less contact resistance. If your dedicated line is shielded of (better) starquad wired you also get less antenna effect and less inductance on your line. Combine this with a star wired distribution block, and some nice power cables (Puritan for example) Your system can now pull, "cleaner", current more effectively. The power supplies have an easier time converting AC/DC. Voila, better sound.