Paul S wrote:

Although "consistent" AC might be something equipment designers could allow for, I think the problems we are dealing with are both myriad and systemic, and we are probably stuck with these problems or some other systemic issues, until we develop some other energy source, or at least another way to deliver it.

rowuk wrote:

Do we simply not want a non-changing target? As regeneration does not seem to be „the“ solution (especially if the AC cord behind the regenerator changes bass), what does better AC even mean? Perhaps the designers of great equipment need to rethink power supply architecture. Our power source will not get better over time. The drive to eliminate coal and atomic reactors does not leave us with a whole lot of options. Regenerative power, especially solar is not consistent and we do not have really good methods to store excess power.  For my own system, the weather plays a bigger part than the electricity. Certain nice things happen when the humidity goes over 60% (more space, denser tone, less noise from LPs).

rowuk wrote:

To answer the philosophical questions first - at least from my view:

rowuk wrote:

All apply, are measurable, BUT we have no correlation of the measurement to the brain of the listener(s).

rowuk wrote:

We are all ultimately responsible for our own behavior, so I believe that the personal perception is the issue to target. My experience with continuous musical training constantly shows me how much "control" we have over our perception. We have syllabuses to train musicians but not listeners of music. This pretty much means that all results for "audiophiles" are more chance than plan.

ArmAlex wrote:

Quality of electricity in recording studio is irrelevant, we hear what it is, as it is.

Romy the Cat wrote:

ArmAlex wrote: Quality of electricity in recording studio is irrelevant, we hear what it is, as it is. Unfortunately you are very wrong about that. Put in this way:  I would not use the word “irrelevant”. It is very much relevant but it is rather not manageable for the people who deal with audio recordings that already took place. Maybe I abbreviated my sentence too much. I meant, or I should had wrote, It's irrelevant to bring in a factor which we have zero influence in it.

JOHNR wrote:

One of the things that I picked up in this thread is the fact that if you use 2 PSUs in series, the sound degrades.This is typical of one unit generating common mode noise and this adds to that produced by the second unit.Even if you run them in parallel and driving different parts of the system, the cumulative effect will remain.Common mode noise passes through all electronic systems unless properly treated. Let me explain common mode noise first.When diodes are used to convert a.c. to d.c. they generate this type of noise.The self capacitance of the device is charged and discharged with each waveform transition.  This creates  a tiny current pulse in series with the output voltage.This pulse has no energy and appears on the two output rails as a pulse having the same polarity on each rail.  Therefore, each rail goes up and down together thus the voltage does not change.  An oscilloscope does not show this pulse.  A capacitor does not respond to this pulse either since the voltage on each terminal goes up and down at same time. The only way to filter this noise is to use a current compensated choke; aka a common mode choke.  This device will absorb the pulse appearing on each winding therefore self cancels.If you take any commercial product you will only find one of these on the a.c. input.  You will rarely find any on the d.c. side of a circuit.What you will also find is that the choke that is used meets a very rudimentary specification and is less that useful in keeping noise out of other circuits in a  system.  This explains why switched mode systems have a bad name, they corrupt everything else. I will continue this in a follow on email.RegardsJohn

JOHNR wrote:

One of the things that I picked up in this thread is the fact that if you use 2 PSUs in series, the sound degrades.This is typical of one unit generating common mode noise and this adds to that produced by the second unit.Even if you run them in parallel and driving different parts of the system, the cumulative effect will remain.Common mode noise passes through all electronic systems unless properly treated. Let me explain common mode noise first.When diodes are used to convert a.c. to d.c. they generate this type of noise.The self capacitance of the device is charged and discharged with each waveform transition.  This creates  a tiny current pulse in series with the output voltage.This pulse has no energy and appears on the two output rails as a pulse having the same polarity on each rail.  Therefore, each rail goes up and down together thus the voltage does not change.  An oscilloscope does not show this pulse.  A capacitor does not respond to this pulse either since the voltage on each terminal goes up and down at same time. The only way to filter this noise is to use a current compensated choke; aka a common mode choke.  This device will absorb the pulse appearing on each winding therefore self cancels.If you take any commercial product you will only find one of these on the a.c. input.  You will rarely find any on the d.c. side of a circuit.What you will also find is that the choke that is used meets a very rudimentary specification and is less that useful in keeping noise out of other circuits in a  system.  This explains why switched mode systems have a bad name, they corrupt everything else. I will continue this in a follow on email.RegardsJohn

rowuk wrote:

Alex, I have a APC RT UPS which is a regenerator and UPS in one. I use it for on site recording as you never know what you get from the wall socket. Dimmed lights, PA and all sorts of other devices like air conditioning and refrigeration are plugged in randomly at those venues. For especially bad situations, the device has enough charge for operation of the recording devices and mix board for about 11 hours. In the last 15 years, I have only needed the DC operation once. The APC RT successfully „fixes“ these problems - at least in the context of a mixing board, multi channel ADC/DAC, PC for recording and kilometers of microphone cable. Perhaps the problems in the recordings are not as prevalent because power amplifiers are affected not small signal devices? I do not know. This thread is many years old and it seems that no one that has the problem gets universal relief from the „PurePower“ or other device. Seeing how Alex introduced the idea that power cords between the PurePower and mains change bass shows me that this is not a „solution“ but a deficiency in the PurePower device. If I did have this problem of dramatic variable sound quality due to grid influences, I probably would make notes of when it is not so bad and move my listening to those times. In any case, my personal opinion remains. This phenomena should be solvable by „better“ power supply design. Until we know what causes the problem, there is no way to define better. As we leave coal and atomic energy, I suspect that things will get worse - maybe so bad that some smart people will do something ingenious.

Amir wrote:

Pure Power Solution is over 90% effective

Romy the Cat wrote:

PP does inject very positive qualities to sound and it is in part might be because it addresses some of intricate electric problems but we, or at least I, do not know it with certainly. The claims that PP manufacturers make is irrelevant to reality.

Romy the Cat wrote:

partially because we do not know what certainty what constitute “electricity problems” and how sound related to the thing that we do know about electricity.