Multichannel amp- Butler 5150 vs. Lexicon RX7

Currently my home theater includes a Lexicon MC12, a Lexicon RX7 amp, and PSB custom in cabinet speakers. I have had this system for quite some time, but I have become somewhat less than satisfied with the audio quality. I am looking to achieve a smoother, more analog-type sound and as a result I have purchased a Conrad Johnson MET1 6 channel analog preamp. I am also debating as to whether a change to a Butler 5150 would lead to an improvement in overall sound quality as compared to my Lexicon RX7. Any thoughts, or suggestions?
I am a big fan of the Butler products. A 5150 would be a great way to inject tube sound into a HT system, without the heat and hassle of so many channels of tube sound.
Have not heard the Lexicon amp so cannot compare, but the Butler TDB 5150 has been an excellent addition to my HT system and has performed flawlessly for about 6-7 years now.

It's not super +tubey" sounding; I'd describe it as somewhere in between a classic push-pull tube amp (with some negative feedback) and a warm SS amp overall.