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
Is intermodulation better understood as a fluctuation of voltage or a fluctuation of current? I understand that you can't change one without changing the other (Ohm's law), so maybe that question is meaningless. I would just like to have a better mental picture of what those electrons are doing! :-)
It's best to think of everything I have described in terms of voltage. The current at any given point in the signal path is what it is, based on Ohm's Law.

One reason that all of this tends to be confusing is that the statement which is sometimes seen that the power supply is in the signal path, since it supplies the current that drives the next component in the chain, is a bit misleading.

Yes, in addition to powering the internal circuitry of an amplifier the power supply supplies the current that drives the speakers (supplying it via the transistors or tubes + transformer in the output stage of the amplifier). But a better way to think of it, IMO, is that the output stage of the amplifier will generate a voltage that at any instant of time is (to a close approximation) proportional to the voltage at the input of the amplifier at that instant (actually, slightly before that instant, because it takes a very small but non-zero amount of time for the signal to propagate through the amplifier). The power supply will then provide to the output, via the output transistors or tubes + transformer, whatever amount of current is necessary to establish that output voltage across the load resistance or impedance, consistent with Ohm's Law.

Best,
-- Al
...the output stage of the amplifier will generate a voltage that at any instant of time is (to a close approximation) proportional to the voltage at the input of the amplifier at that instant... The power supply will then provide to the output, via the output transistors or tubes + transformer, whatever amount of current is necessary to establish that output voltage across the load resistance or impedance, consistent with Ohm's Law.

That is very helpful, Al, and different from how I was thinking about it. Thank you for your heroic patience while explaining these things!

Bryon
How do you determine whether to buy a 15 amp or 20 amp power conditioner? Simply by the size of the AC circuit it is plugged into or are there other factors like the demands of the audio system?
Hi Lynne,

What is relevant is the maximum amount of current that is demanded by the audio system. As long as a 15A rating would provide a reasonable amount of margin with respect to that demand (and I suspect that it will in your case, assuming that you will not be using a powered sub), there is no problem using a 15A conditioner on a 20A line.

Best regards,
-- Al