Passive Pre-amp: Improves overall sound quality??

How could a passive preamp improve the sound of the amplifier?

Anyone.....

Thanks to all have been responded. I have now begun my reschooling in basic electronics.

BTW, Brownsfan: Sam's current wunderlich (I know, bad pun) is the Music First Passive pre-amps. He wants to (again) do away with all active pre-amp because of all the "nasties" they ad to the music. Yes, but at what price and convenience??

If set up correctly, a passive preamp can sound as good or better than the some of the best active preamps out there. In my system, I have a high quality stepped attenuator built into the input section of my amp. Keep the interconnect 6 feet or less from digital source to amp and make sure the input impedance of the amp is at least 10x higher than the output impedance of the source. All digital source these days have enough output voltage to drive most amps to clipping. If you listen to vinyl, it gets more complicated. This is by far the best "Preamp" I've had in my system in 25+ years.

The best preamp I've had in my system is transformer-based and available sometimes for peanuts on ebay.fr:

Search for the Redson RC-1080

Sounds real audio, it can't and to those in the passive camp that is a good thing?