Why does better power = better sound?


Why does improving power quality improve sound quality?

I’m not asking to start an argument about power cords or wall outlets. Please let’s not go there. I’m asking because I’m hoping to learn some technical explanations for the effects of power quality on sound quality. I think I already understand how…

1. greater current availability = greater dynamic range
2. reduction of RFI/EMI = better signal to noise ratio

…but what about these…

3. ???????? = greater perceived resolution
4. ???????? = more realistic instrument timbres
5. ???????? = more precise imaging

Are differences in resolution, instrument timbres, imaging, etc. somehow reducible to current availability and/or powerline noise? If so, HOW are they reducible?

Again, I’m hoping to get into technical specifics, not polemical generalities.

Thanks in advance.

Bryon
bryoncunningham
Bryon, when you speak of power quality, I assume you are talking about the quality of the AC line, correct? The age old question about why our systems sound better at night? When there is less stress on the power grids and the electricity is better quality? Or dedicated lines taking things like refrigerators or air compressors off the lines of our audio equipment?

If so, I think the answer is just the equipment is better able to perform to the best of it's ability when it is driven with better, cleaner power. When fed dirty power, any piece of gear can struggle. That is why some manufacturer's believe that a battery supply (DC) is the only way to provide true clean power. I believe the answer to your questions 3,4 and 5 is simply that with cleaner power, the equipment is getting what it needs to reveal it's potential sound quality.

I suppose it is similar to how a car performs using different octane levels of gasoline. Yes, in cars too, some manufacturers believe that a battery is the best source for clean power.

Cheers,
John
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It probably has to do with non-optimal power supplies in equipment that cannot fully eliminate harmonic impurities or adequately deal with small scale fluctuations in power line frequency.
3 and 4 is same as 1 and 2 - greater dynamic range requires good current delivery and low noise.
Instruments won't have natural timbre thru noisy gear that compresses dynamics.

5 - Imaging is related to noise as well but also to crosstalk, often thru common power supply. Power amp supplies are most likely without line and load regulation with inductive capacitors. Separate power supplies for each channel or even separated amplifiers (monoblocks) will reduce crosstalk.

Jeff Rowland started using sophisticated switching power supplies in latest model 625 (class AB power amp). It switches at 1MHz (easy to filter out) with zero voltage/ zero current switching. It delivers clean voltage that is line and load regulated (not to mention efficiency).

Linear power supply is also a switcher operating at 120Hz where switching appears in worst possible place - at maximum AC voltage. Current is supplied from mains in sharp narrow spikes. Width of these spikes changes with load (switcher's definition). 120Hz ripple is difficult to filter out and requires a lot capacitors. Transformer has to be huge for good performance. In comparison same power transformer operating at 100kHz can be 10x smaller. That's the future in my opinion. Jeff Rowland already uses switching supplies to obtain low noise in preamps (Capri) where efficiency is secondary issue.
…but what about these…

3. ???????? = greater perceived resolution
4. ???????? = more realistic instrument timbres
5. ???????? = more precise imaging
I believe that several before me have already hinted strongly at it - lower distortion equals better resolution, timbres & imaging. So, better power implies "better quality power". It's all about the linearity of the power amp & the ability of the power supply to supply sufficient voltage headroom (so that the voltage excursions do not clip) & dynamic current into the load (so that voltage swings do not clip & sufficient voltage can be created in the drivers so that they in turn can react pistonically assuming that the speakers can handle to volume SPL).