Is no preamp really better that a good preamp?

It really depends on the quality of the volume control. According to many, analog volume controls using sound better in most systems. Passives too, but the gain issue then comes into play for many.
IMHE, usually an active preamp with analog volume sounds best to most ears. A good tube preamp like the Cary SLP05, Modwright, Backert Labs, Audio Research, Herron, BAT..many options all are good choices.
You can try a cheap pair of passive attenuators for an idea of passisves in your rig. Of course, I'd borrow/demo a preamp first if possible. Cheers,
Spencer

Oh boy. *grabs popcorn*

The answer is ... it depends.

A good pre-amp will add a distinctive sound of its own. You'd have to try one and compare to not using one to know for sure which sounds better to you.

+1 Mapman.

Having enough gain in a source component is not all that is necessary to get the best sound out of that component. The output stage of a good pre-amp is engineered to drive the input stage of a power amp, while any given DAC or phono stage may or may not be.

In a related topic, it is for the same reason that many listeners (no pun intended---see below ;-) find the sound of a passive pre-"amp" to lack something (see Art Dudley's column in the current Stereophile).