Maybe a dumb question about preamps


I am considering to purchase Bryston 4Bst or 4Bsst. Do you absolutely need to connect them to a preamp or can they run by itself and still achieve the sound quality that they are intended to produce. If preamp needed, would it be appropriate to connect to a Pioneer Elite 52TX that I have and use it as a preamp. Thanks for your advice.
desireforsound
On the other hand, if your source doesn't control the volume then use your Pioneer's ''Pre Outs'' and use it as a Preamp.
The Bryston 4BST is connected to the pre-out from the Pioneer Elite for the two front speakers with Music Hall CD25 for music, Samsund DVD for HT. I have to use the attenuator from the Pioneer or else the sound clips even at low volumes. Any better suggestions for hook-up or components that I may need to add to obtain better sound quality from the Music Hall, Bryston amp and Pioneer pre-out? Thanks again for your suggestions.