How in g**s name can a active preamp give you more REAL detail (not perceived detail because of distortions) from the source than the same well match direct source to poweramp.??
Please produce some laws of electronics in your answer and not voodoo speak.
The answer to this was in my prior post. However I like to use engineering principles since you asked; we can start there... normally in any situation where we are driving a load, as a general rule of thumb the source will have about 1/10th the impedance of the load. This is a good practice to insure proper bandwidth and low distortion of the source.
When you put a resistance in series with the source, the source will begin to have troubles driving the load. Now when the series element is a volume control, one might argue that the control itself becomes the source but this is not entirely accurate. The source becomes that of the volume control and the original source together, along with whatever effects are imposed by the interconnect cable between the source and the volume control. Many sources use a coupling capacitor at their output; such sources can suffer frequency response aberrations when a series resistance is imposed between the source and the load it has to drive (which in most cases will be an interconnect cable and the input of an amplifier).
Generally speaking, these errors can be reduces if the source is of low output impedance and the volume control is a fairly low value, for example 10K ohms or less. The issue here is the ability of the source to drive such a load, but if that is the case the effects of the cable between the PVC and the input of the amp will be better controlled and the series resistance between the source's output coupling cap and the amplifier's input will not likely impose much of a frequency response error.
When you get into higher source impedance and higher volume control values the cables play a larger role. This is partially due to capacitance. You can calculate the minus upper 3db point by the formula f=1,000,000/2xPi x C x R, where R is the source resistance in ohms, C is the capacitance to ground (that of the interconnect cable) in microfarads and f is the -3db point in cycles per second.
The cable between the source and the volume control should not be ignored.
While the ear cannot detect phase shift of individual frequencies, it can detect phase shift in a band of frequencies (generally as a tonality but high frequency phase shift can also affect imaging), generally phase shift effects can be heard to 1/10th the cutoff frequency, so if your -3db point is at 50KHz, there will be effects down to about 5KHz.
When you put a PVC after a source, as far as the amp is concerned the output impedance of the source is increased, conversely from the perspective of the source the load impedance is decreased. This can lead to the low frequency cutoff being increased in frequency. To avoid phase shift in the audio passband, the cutoff should be about 2Hz as phase shift components (which to the ear sound like a loss of impact) can be heard to 10x the cutoff frequency. So of this moves from 2Hz to 5Hz phase shift components can have an effect at 50Hz rather than 20Hz.
Thus it can be seen that while a PVC is a very simple device, if incorrectly used it can act as a simple passband filter. Keeping the phase shift components out of the audio passband is the key to success and is why they can work so well in some systems but not in others.
we are discussing about what the OP's question is, stop rambling about passives, GET A GRIP MATE.
"Is no preamp really better that a good preamp"
And I also addressed this in my prior post, which (in a nutshell) says that in some cases a passive will be better and in others an active will be better, thus both must be auditioned. I thought you would be happy that I was agreeing with you that passives can work...