I've been using the Promitheus Reference C-core TVC since I got my first Musician III SE. I'm using all balanced interconnects throughout the system.
It's quite puzzling to me that something so affordable could sound so good. It simply lets the signal from the source get to the amps without adding anything, and most importantly, without removing anything.
This TVC is completely quiet using the balanced interconnects. I've been trying all along to find any area that it may be compromising, but to these ears it gets most of the things right. It doesn't have the mid-range magic that tubes provide, but it's close to it. And it does this while maintaining deep, controlled, fast, and articulate bass. The highs are crystal clear without being edgy or mechanical. The sound is simply completely clean from top to bottom.
I tried this TVC with single ended interconnects and it was picking up some hum if I set the volume almost all the way up without music playing. This disappeared entirely when I switched to balanced interconnects.
The one major requirement for this TVC to work is that you need to have enough gain in the system. Without enough gain, it might not do what it's supposed to do.