I think you were generalizing that Actives were better than passives. I do not think I attacked your statement in any way. I was suggesting that we cannot make generalized statements. Isn't TVC a passive component?
No worries- but apparently what you were thinking is not exactly what I was saying since I was careful to not generalize. If you review my posts you will see that I make a point of also saying that not all active line sections are created equal. The phrase I like to use goes like this: 'It is a statement of how poor many line stages are that passive volume controls can beat them'. So I am always careful to use the phrase 'properly designed'.
So far this thread has really been about active preamps vs PVCs (Passive Volume Controls).
TVCs (Transformer Volume Controls) should not be considered in the same realm as PVCs. The math regarding how they function is quite different.
TVCs involve a transformer or autoformer with taps. They have a different set of issues- for example if improperly loaded the device will not express the turns ratio correctly and so bandwidth will not be flat (inter-winding capacitance can start playing a role). This means that the designer has to provide the proper loading for each step in the setup, taking into account that the amplifier (which might have an input impedance anywhere from 10K to 100K or more) is part of that load.
A lot of TVC designers don't take all that into account. So some of them are easily beaten by active line stages because the active unit is more tonally neutral). OTOH, there are TVCs that have all the design parameters sorted out and they can have impressive performance if used correctly.
If a TVC provides gain (and sometimes even if it does not) and depending on the type of amplifier used, the interconnect cable may well play a serious role in the results! Cables have capacitance and TVCs are all about inductance- the two together can result in a high frequency resonance that varies with the control setting.
If you can hear big differences between interconnect cables, what you can safely conclude is that the 'good' cable you have now and the one that didn't make it are both wrong. The why of it is simple- did you audition all the cables out there? Will the manufacturer of the cable you settled for make a better one next year?
A properly designed active preamp eliminates this issue- the cable plays a far less of a role in the tonality and resolution of the system. A good active will force the cable to do its job- to pass the signal without editorial. I don't see PVCs or TVCs really doing that.