Linear Power supplies for DACs...?

LINEAR POWER SUPPLIES CAUSE HUM

The noise problem is due to the fact that linear power supplies have large transformers and other magnetic components that operate at the AC line frequency (50 Hz to 60 Hz). These line frequencies are audible, and we are all too familiar with the hum and buzz that audio products can produce. It is no secret that this noise is caused by the power supply, but few people understand why it can be so hard to eliminate. Most people think that hum is caused by conducted interference (AC ripple on the power supply rails), but this is rarely the case. Most AC hum is caused by magnetic interference, and this can be very hard to eliminate.

Anyway I wasn't referring to only LPS or power supply  in general  but any noise in the signal that can get to the speakers. Power supply or transformer hum is harder to get rid of short of replacing the offending item or getting rid of the component. 

djones51
Power supply or transformer hum is harder to get rid of short of replacing the offending item or getting rid of the component.

No, not really.

Hum in a system could have several causes:

- DC offset
- ground differential
- bad capacitor 
- a fluorescent ballast on the same or another circuit
- a dimmer lighting switch on the same or different circuit
- poor grounding
- a poorly sealed transformer
- loose nut(s) on a transformer
. . . and more

In the three residences, I’ve lived in the past 20 years, hum has been completely eliminated each time depending on the cause. None of the cures included replacing any equipment at all. I’ve never had a LPS that caused a hum whatsoever. Each LPS significantly improved the SQ. They generated clean power.

I've lived in 8 residences in the last 20 years and never had or heard any hum. I've never noticed it with wall warts or linear in amps. This thread is about DACs and if a linear would improve or is it placebo so whether you use linear, switched that came with the DAC it doesn't  really matter since we don't  listen to those wires anyway their waveforms are filtered by the DAC.