TVC preamps: good or bad?

I don't know if they introduce colorations and aberrations, but they do seem to be very transparent and quiet and don't appear to be much bother by impedance matching issues that you sometimes get with resistor based passives. Some folks with pretty good equipment seem to swear by them, especially the Bent units and those made with S&B transformers.

I'm curious and a bit confused about these as well. On the one hand these transformer based units seem to offer much the bonuses of passives, without the impedance issues of passives. On then other hand, some tube manufacturers are willing to deal with impedance issues to avoid using transformers. Some of those same manufacturers claim that transformers introduce phase issues. What's the real story?

I currently have Promitheus Audio Reference C-core TVC and I can confirm that this unit is extremely transparent and extremely quiet. Soundstage definition and resolution is the best I've heard in any system at any price. Each instrument has its own well defined space. Dynamic contrast is top notch. This TVC doesn't have the midrange magic that tubes provide, but it gets pretty close.

This is the top-of-the-line TVC that Promitheus Audio makes, so I don't know how their other units compare to this one. From what I've read, these TVCs don't work well on systems where there is not enough gain. I don't have that problem at all. The sound is already too loud if I pass the 1 o'clock mark.

Regards,

iSanchez

As far as I know resistors also introduce colorations. TVC is just most transparent and neutral preamp solution I have ever tested. It lets you hear everything that your other components will allow. It doesn`t add any warm or cold colorations. If other components sound good it will sound good and if other components sound bad it will sound bad. It is dead neutral. I usually don`t go very deep about different technical theory's. I just listen and keep what sounds best. If sound matters most there are no cons with TVC. I am pretty sure that a good TVC can stand against any preamp prize no object. It seems that this is just superior technical solution. Just don`t place it near power amp because hum may appear. I suggest you to find some balanced Promitheus TVC. With balanced connections there will not any hum problem. These usually go for some $500 used and you can sell it at same prize if you dont`t like it.

Thank you everyone for your responses. I think that Unsound has rephrased my question very well. I am hoping that someone with more technical knowledge will come along and shed some light on the subject.

I have heard a passive TVC pre in my system and I was not impressed. But I know better than to generalize a single bad experience to the technology as a whole.

BTW, I am not looking to buy a TVC preamp ... so please don't email me with offers to sell me one :)