Can a Quad DAC equipped smartphone output superior analog sound when plugged into an USB power source?

[Tortie]

Last year another ASR member reported that they unintentionally obtained superior sound quality from their LG smartphone by having it plugged into a USB charger. This could possibly be a placebo affect but the ASR member noted in his 2021 post that he experienced this "improvement" with two different headphones, one a DT990 and the other a set of efficient IEMs.

If I understand correctly how power works on phones when they are plugged into a power source the phone both runs off the external power source while the battery charges.

Is it possible that LG phones, and possibly other manufacturers, have built-in design power management features that deactivated when a phone is charging?

This question has me pondering if powering my LG V20, or any Quad DAC equipped smartphone, with a portable USB battery bank could yield better sonic performance.

 

[antcollinet]

I very much doubt it. As well as the impact of power regulation from the battery, you are also going to get any noise coming in from the external switching power supply.

It would have to be measured to be certain, but I'd expect any difference to be inaudible.

 

[Jimbob54]

I very much doubt it. As well as the impact of power regulation from the battery, you are also going to get any noise coming in from the external switching power supply.

It would have to be measured to be certain, but I'd expect any difference to be inaudible.

Pretty easy blind test to do though as I imagine levels etc should stay the same (or would be noticed if they changed) . Loop a track or segment of one, friend either plugs in or removes power supply from phone between playback loops with subject blinded. Easier for Joe Bloggs to conclude from that if there is a change/ preference than measurements.

It would be disappointing to say the least to see a phone marketed partly on its audio capabilities to be throttled when in the state it spends 90+ % of its life in.

 

[Tortie]

I very much doubt it. As well as the impact of power regulation from the battery, you are also going to get any noise coming in from the external switching power supply.

It would have to be measured to be certain, but I'd expect any difference to be inaudible.

It did seem like a case of placebo effect. But another explanation is that this particular person simply had a failing battery in his V20 that was impacting the functions of the phone.

 

[Tortie]

Pretty easy blind test to do though as I imagine levels etc should stay the same (or would be noticed if they changed) . Loop a track or segment of one, friend either plugs in or removes power supply from phone between playback loops with subject blinded. Easier for Joe Bloggs to conclude from that if there is a change/ preference than measurements.

It would be disappointing to say the least to see a phone marketed partly on its audio capabilities to be throttled when in the state it spends 90+ % of its life in.

Indeed it would and I would normally doubt this could be the case but LG's design "feature" that steps down the output voltage for low impedance headphones and external devices gives me pause.

Thanks for the blind test idea. I'll have to give that a try.

 

[ZolaIII]

All chances are it will perform worse (in case of any equipment battery vs grid and transformer). Vendor's are keen to implement all sorts of loudness limitations to local laws and regulations, LG whosent any different. On all newer QC SoC's there is a higher quality and bit higher gain stage (G-H class operation mode) which isn't used from any vendor because it sips more power (still not significantly more compared to whole SoC). As I have couple things with old ES combo (ES9018K2M + SABRE9601) including in portabl and battery powered based on reference development board one I can say LG got the great job regarding implementation rest is now history.