It depends entirely on the output capabilities of your source, and the sensitivity of your amp(s). If the source has the drive to achieve the SPLs you enjoy with your amp/speaker combo, you'll be happy. I thoroughly enjoyed the transparency I experienced with only a Placette Passive Linestage, and with MOST sources had all the dynamics, sound stage, extension, etc recorded on the disc. BUT: With those that were recorded at lower levels(some of my favorites) there was inadequate signal. Now I'm using a TacT pre that gives me just enough gain to overcome the differences in my discs, is still very transparent, and gives me a bunch of flexibility with regards to time domain and room tuning. Then again- There are a lot of people that enjoy the various things that pre-amps add to(or take away from) the music. Some mistake grain for detail, microphonics for warmth, etc. Then it becomes a matter of personal tastes as to what is "right" for them.
Will adding a preamp dramatically change my sound?
You can link to my system below, but basically it is a Cary CD player with internal analog volume control direct to a Spectron Musician II amplifier into Totem Forest Speakers, with quality cables and power cords. Honestly I don't feel anything is lacking, but still find myself getting curious about what effect a preamp would have. Anyone have any experience going from a CD direct to amplifier, and later adding a preamplifier? To what result?