I used to think passive preamps were superior to active preamps given right the setup, but

The best preamp is no preamp?...  Possibly... but only if the recording was perfect and recorded in an ideal space with phenomenal room acoustics.   Otherwise?  I still prefer Technicolor movies over the plain variety. I know..  Not real... But,  so much more pleasing and stimulating to your soul.  After all, that is why we seek to listen to music! Recording engineers know this.  That is why they will often times add effects and enhancements to what was recorded. 

I learned my big lesson when I began op-amp swapping with my high quality pre-amp/phone amp.  No piece of equipment is neutral.  Even the passive ones. For there are various kinds of passive preamps that produce different sound!  So? Create your own "neutrality" of sound.  One that produces a believable sound that YOU THOROUGHLY ENJOY.   Not one we are to be told is enjoyable but does not quite move you. It always has to be quality - low noise - design. That never varies.
 C'est la vie.

Genes,

"Create your own "neutrality" of sound. One that produces a believable sound that YOU THOROUGHLY ENJOY. Not one we are to be told is enjoyable but does not quite move you. It always has to be quality - low noise - design. That never varies.
C'est la vie."

Sage advice. You're a true philosopher. But there are many in high end who will try to convince you what the "truth" should be and what should be "enjoyable". And they will charge an arm and a leg for it.

"The best preamp is no preamp?... Possibly... but only if the recording was perfect and recorded in an ideal space with phenomenal room acoustics.   Otherwise? I still prefer Technicolor movies over the plain variety. I know.. Not real... But, so much more pleasing and stimulating to your soul. After all, that is why we seek to listen to music! Recording engineers know this. That is why they will often times add effects and enhancements to what was recorded.  

I learned my big lesson when I began op-amp swapping with my high quality pre-amp/phone amp. No piece of equipment is neutral. Even the passive ones. For there are various kinds of passive preamps that produce different sound! So? Create your own "neutrality" of sound. One that produces a believable sound that YOU THOROUGHLY ENJOY.   Not one we are to be told is enjoyable but does not quite move you. It always has to be quality - low noise - design. That never varies. 
 C'est la vie."

+++++++++++++1, Genez !!!!!!!

J. :):):):):):):):)

A typical explanation for why passives sometimes don’t perform as well as actives is that the source doesn’t have enough voltage/current to push the signal through a passive to the amp. I think this was even mentioned by someone in this thread. While that can be true, I submit that this is all too often misunderstood and not the limiting issue.

Regardless of the line source type (CD, DAC, phono stage etc.), that source doesn’t know whether it’s connected to a passive or active preamp. All it "sees" is the impedance it’s driving into. If that impedance gets too low the source’s output stage won’t be strong enough (current capacity) to deliver the voltage signal properly because the current demand is too high (resulting in poor dynamics, flabby bass etc. ).

With active preamps, the source sees only the input impedance of the active preamp - typically 10k or higher. With passive preamps (resistive types like pots, stepped attenuators and LDRs), the source sees the combined impedance of the passive preamp in parallel with the amp.

If the passive has a stand alone input impedance of say 20k and is connected to an amp that also has a 20k input impedance, the combined effective impedance seen by the connected source is 10k. No different that the active in the above example.

If a given passive with a decent inherent input impedance disappoints relative to an active alternative, I would submit it’s not simply because the source can’t deliver the goods.

The related question of impedance matching (sufficient impedance bridging) is the number one topic with passive preamps. What we’ve found in actual practice with our LDR preamps in combination with countless different customer sources and amps is that impedance matching is rarely a limiting factor.

For what it's worth, Emmanual Go, producer of the superb lineup of First Sound tube preamps initially marketed a passive preamp.  Eventually he began to engineer, manufacture, and sell dual mono actives with separate power supplies.  I recently paid Mr. Go to install the two "S" upgrades in my FSPD III and an incredibly quiet, dynamic, and musical preamp jumped yet another notch in performance.  It is the only component I've owned during 45 engaged in this hobby that I've never considered selling.