[rsbrsvp]

I have a Mojo Audio ultra low noise linear power supply for my mac mini.  The manufacturer claims it is around 20% lower noise than lithium batteries.  I clearly hear the difference over that mac mini with the switching power supply.
 
Someone claimed to me that even though the mac now has a linear power supply, the usb outputs of the mac still run on a switching power supply.  I don't understand how that could be possible.
 
Is that correct or is the usb output power considered linear power if I have a linear power supply on the mac mini?
 
I would appreciate the correct answer to this question.

 

[Hi Rez]

I have a hard time understanding that myself, as switching power supplies use AC inputs, and you are feeding a DC input into your mac mini.  I would ignore the claim and enjoy the music.
 
btw, I also found the dc conversion of my mini to provide a nice bump in sound quality.

 

[Roseval]

Your linear PSU probably supplies 12 V but USB needs 5 V
A mobo has various components working with a different voltage.
On the mobo there are several voltage regulators and they are indeed switchers (PWM)

 

[Hi Rez]

  Your linear PSU probably supplies 12 V but USB needs 5 V
A mobo has various components working with a different voltage.
On the mobo there are several voltage regulators and they are indeed switchers (PWM)

Thanks for the post - was unaware before it that dc voltage regulation wouldn't always be linear.  Better searches (Google) explains a lot.