I only have the original grey MDF version, although it has been modified to have a selector switch and an added input (Serge would cringe if he read this). It's still better than any active preamp I have heard (when used in the right system), and clearly better than the MFA was (although at 2x the price).
I use a Promitheus Reference C-Core TVC. Compared it with a 4k active preamp and sent the preamp back. I know what you mean. It is ABSOLUTELY necessary to have "enough" gain in your system for the TVC to work. Also it is very important to choose a loudspeaker with high sensitivity to make the TVC work it's magic in the system. I do not care for impedance or other stuff while using TVC. But "gain" and "sensitivity" are the key words here.
You must have a verified phone number and physical address in order to post in the Audiogon Forums. Please return to Audiogon.com and complete this step. If you have any questions please contact Support.