I would say "blow away" is a harsh term. I have participated in and side with the view that TVCs are better than resistor based passives. Maybe in some systems these "blow away" comparisons could be true, but the opposite could easily be true as well. I would say impedance matching is less of an issue with a TVC, which is very important when using any type of passive. In my system a TVC worked better from an impedance perspective and performed better than any resistor passive I have tried. However I have not tried them all, especially the Placette or First Sound, which are among the best from what I have read (funny Guy and Emmanuel both feel their active preamps are better).
Attenuators and their implementation are very important no matter whether it is in an active or passive preamp. I am now using an active preamp with premium 45 step Shallco volume switches, but the 19 step Seiden switches in my TVC were no slouch either. Funny though how my Joule LA-100 MkIII did just fine with basic dual volume pots.
As you know Roger's pot in a box uses a 40 year old switch with great results. Some also swear by the Penny & Giles, Gold Point, and DaCT switches. Intact Audio sells custom switches for their autoformers (a custom version of which will be used in the new Bent TAP from what I have heard). The possibilities are endless.
What will be more interesting to me are your observations as you try these options. Please let us know what you think as you have had the opportunity to hear many excellent active and passive preamps in your system.
