Help choose best amp/preamp combo?

Hi there
I am new to audio forum.Helo every one here can help me.I do build a 2 channel stereo with JBL sub.here is my system :Parasound a21 amp + Emotiva xsp1(gen 2)+ pair of B&W 805 Nautilus.To be honest, I do loved the sound system very clear and crisp on high and midrange with powerful bass tights.but it is LACKing of Warm sound.I do loved the warm sound is top priority.couple months ago I do have Rotel 1095 amp pair with Rotel rsp1570 + b&w cdm1 Nt sound is clear crisp and WARMER but sound is THIN compare to Parasound.but Rotel sound is warm which I like much.I also heard that Parasound a21 is warm sound too.but in my taste it is not.my question is the amp do produce a warm sound or Pre-amp produce a warm sound or the speaker do make the sound warm?I am confused and I want change my system to Rotel rb1582mk2 + Rotel rc1580 pre-amp because I heard that B&W speaker and Rotel is relate to each other and their product is matching together in sound.especially BW speakers is sound good with Rotel amp.is this true.and how you guy advised me to keep Parasound a21 and changing Pre-amp to either Parasound P5 or Rotel rc1580? Or go full system with Rotel like Rotel rb1582mk2 + Rotel rc1580?I am confused now and need your help.Thank You in advance.