I'm considering replacing my passive preamp with a tubes. Is it worth it?

http://www.thetubestore.com/Tubes/6922-E88CC-Tube-Types/Telefunken-E88CC-6922

I have a Bent Audio AVC passive and a VAC Phi Beta tube preamp in my rack, along with a high input gain tube amp (VAC) and SS amp (Plinius). The Bent sounds great with both amps but I always go back to the tube preamp for the bigger, more solid sound stage it throws, and the improved low-mids.

That being said, I have heard a Music First Baby Reference passive in this system and that was truly special. It lacked for nothing. Great piece of gear.

From Audible Illusions... If you have not already made a decision, you might want to try a used AI Modulus 3 or 3A. It is a perfect match for that Bryston and the Maggies.

@wrm57,
The Music First is a TVC and is not really a passive.
Can you please let me know what you "lost" in sound, when you introduced the Music First in your system, compared to the VAC Phi Beta? How would you compare the Music First Vs Bent Audio AVC?