TVC preamps: good or bad?

Atmasphere, while opinions vary on whether a passive preamp can surpass a top-notch active preamp, there seem to be a number of posters who find TVC passives preferable to resistive passives. I don't think I've ever read anyone comment that they prefer a resistive passive to a TVC. Which leads me to wonder, how would a TVC or autoformer volume control sound if used in a top quality active preamp in place of a traditional resistive attenuator volume control? Have you ever tried it? Apart from the issue of sonics, there could be a problem with increased cost & available real estate within the preamp chassis. But maybe the ability of a TVC to increase current drive at high voltage attenuation might off-set somewhat its other theoretical compromises.

Ktstrain, you obviously know something about the subject. Do you think an AVC or TVC could be designed to perform as well with a higher impedance source, such as a tube phono stage with an output impedance up to 5K?

Are you using the Bent TAP with your Merlin BBAM upstream or downstream of TVC? If you're having good results, I assume that the BBAM must be upstream. The BBAM's 47K input impedance and capacitive load reportedly don't mate very well with a passive.