TVC Promethius versus Bent


Any impressions on differences from this that have tried TVCs from both these companies? Also, I'm not sure why a transformer would help over of a passive resistor based attenuator (assuming a very high quality pot)assuming drive, low output impedance source, low capacitance cables, high sensitivity amp with high input impedance (100kohm). If more is less, why isn't adding a transformer just more, though minimal, distortion? Sort of two questions, but I have a high quality passive volume control, but have an interest in the TVC idea, especially these two brands or something made by Kevin Carter.
pubul57
I've played with both, it is a tough call IME. Now that Nick has introduced a C core version. Which is supposed to be even better. I personally would try it before any of the others just because of the different winding technique.

The Bent was the better built of the two. It's easy to describe the sound differences between the pot and a TVC.
For me it was like taking a bottle of Windex and a rag and cleaning a cloudy window. This was using a noble pot for comparison..there simply was no comparison in sound.

Bass was cleaner and deeper, the highs had more of a shimmer. And the soundstage layers became more revealing.

The only reason I do not use a TVC now is because I needed more gain for my amplifier. So the results vary depending on the components used. After owning several TVCs, you couldn't give me a component that uses a pot for the volume control..it doesn't matter what it is.
I've never heard the Promitheus, but have made a TVC using Stevens & Billington TX-102's supplied by Bent Audio when they could still be had. Since you ask about
RVC's too, resistor-based passives, let me say that I found my TVC to outperform two RVC's, both using Shallco switches (as does my TVC), one with Holco resistors and one with Audio Note Japan tantalum resistors. Then I made a shunt design RVC using Texas Components TX2352 Vishay resistors, and it competes well (without beating) my RVC. I use low capacitance interconnects, and though they're 9' long I have none of the oft-cited problems with RVC's. Those TX2352 resistors are simply great--I've made huge improvements in three phono preamps by using them as 47K ohms input loading resistors, for example. I hope this info is useful--feel free to email me for more detail.
I don't have personal experience in comparing the Promitheus TVCs to Bent Audio, nor do I have enough personal experience with resistor-based passives to say anything particularly insightful about differences in sound quality in comparison with transformer-based passives. However, I do have extensive experience with the Promitheus dual-box EI-core TVC and the new double C-core dual-box Signature TVC in my SET audio system.

The Promitheus EI-core TVCs are an excellent value with very good sound quality, but Nicholas Chua has really raised the stakes with his new line of C-core based TVCs. The C-core TVCs have more fullness, weight and body to the music and they give you an uncanny sense of presence. If you want to see what a TVC can really do, I can heartily recommend the new C-core TVCs in the Promitheus line of products. The Signature TVC is a force to be reckoned with that, in my audio system, competes very effectively with high end active preamps.
Well, I certainly get the sense that the two brands are very competive with no clear cut winner, which is good as I can sort of decide on price, ergonomics, and aesthetics. I had the Placette RVC which was very clear, neutral and deatailed, but not "plump" enough in the mid bass and bass for me, it seem a bit reticent. Maybe the frequencies were there, but no in-room bloom like I get from my Joule LA 150 MKII, or for that matter the Placette Active which I had transitionig to the Joule. I love the Joule, but I also want a passive for kicks and to have a different sound signature to enjoy. I'm not sure what C-core means since I know nothing at all about electronics, but I take it they perform better that EI transformers - don't know. I hear alot about the S&B tranformers used in the Bent NOH, Tap, and others, are you saying the C-core is a superior technology? I'm not sure I am ever going to really understand this so I'll depend on rational consensus and try one or the other.