Music from a laptop- on AC or via battery power?


I see that in the digital world, linear power supplies are often touted as offering a lower noise environment. 

Suppose I am using a laptop. If I’m running it off the AC, certainly the switch mode power supply is in action. Am I correct in thinking that if I’m running strictly on battery power that the power supply is at lest as clean as an active linear power supply? Or is there sill a switch mode power supply still actively doing its thing in the laptop? 
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Doesn't make the slightest difference on a dirty computer.
Yeccch
Yes. In most cases, the SMPS is in the external adapter which supplies DC to the laptop.
@noromance

Thanks- I thought the SMPS was typically in the external adapter-

Fuzztone- well, at least until I move off the MacBook Pro, i would like to do what I can- I turn off wifi and I run it on battery. But I also think you are right- really can’t hear any significant difference, if any at all, plugged in vs battery

Thank You!
With my MBP I could hear no difference between battery and powered.  There was a near instantaneous improvement in replacing the MBP with a Roon Nucleus.  A much quieter background (lower noise) that let you hear deeper into the music.  I was quite surprised.