TVC Promethius versus Bent

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.

Pubul57, I am also challenged technically, but here is what I know (or, I should say, what I think I know...any of you EE types should feel free to correct me where I go astray): The type of core (EI vs. C in this case) simply describes the shape of the ferrous core in the transformer through which the music signal is effectively transfered from the primary windings (input) to the secondary windings (output) as the result of magnetic inductance. (The signal flowing around the core on the primary windings induces a magnetic flux in the core, which, in turn, induces an electrical signal on the secondary windings.)

With respect to the transformers that Promitheus is using in their TVCs, the EI-core transformer is rather small with comparatively thick core laminations (.35mm). The C-core transformer is much larger and heavier and uses finer laminations in the construction of the core (.05mm). The result is much better sound quality in the bigger and more expensive transformer. The flagship model TVC is the Signature model, which uses a pair of the C-cores in each transformer (one transformer per channel) and also uses more expensive Elma switches as the source selector and volume control. The sound quality of the flagship Signature TVC is significantly better than the EI-core models, which, in and of themselves are very good (and an excellent value).

Since everyones gear and ear is different trying both styles would be best. C-core has always been better to my mind. I want remote and have very well suited gear for a passive setup. I use Placette's w/ 3 inputs and a remote and 125 volume positions. With Vishay S-102 resistors, a logic circuit,relay controlled resistor ladder. No pot. Very nice. I tried a friends Promethius TVC and it was a bit more veiled in the HF and less dynamic.

ET