XLR-RCA-BNC sonic quality differences

Explain the differences in sound produced by XLR-RCA-BNC terminated interconnects in short and long runs. Short being 3-6 feet and long runs being 20-35 feet.

Why do BNC connected cables work so well with amps/pre-amps of DarTZeel? Will that work with others equally?
The main thing about XLRs is the lower noise floor and less potential for hum. When used in a truly balanced system you also have the advantage of 6db more of gain. An XLR uses three conductors. The positive and negative have there own conductors and the ground floats above and below the signal.
I'm really surprised by the lack of answers here.

What I know is that BNC connectors with Coax cable seems to be impressive compared with conventional cabling when using the Dartzeel to Dartzeel combination.

Is that special to the Dartzeels, or is the use of BNC's with long runs of coax beneficial to other setups?

And, would a there be better results using conventional wire and BNC or XLR connectors?
For long runs I would think BNC would be a bad way to go because usually BNC connectors are used for video coax and it is the wrong impedence for audio signals.
The BNC inputs and outputs and their 50 Ohm impedance are unique to the DarTZeel I believe. I cannot think of too many other power amplifiers with a 50 Ohm input impedance. Those on the low side are usually around 5K-10K and many tube amplifiers have input impedances over 100K.

Theoretically the impedance matched BNC to BNC connection would be ideal for extremely long runs with no loss. Note Hervé is using 50 Ohms, not 75 Ohms which is usually specified for video and digital audio applications.

The BNC connection "should" be the best connection between the preamp and power amp because they are impedance matched, versus a typical 600 Ohm output impedance on the preamp driving a 100K power amp input impedance (just an example).

For greater in-depth understanding on why Hervé believes his 50 Ohm impedance matched connections are the best and only way to transmit an audio signal, please read his article in the November 2001 Stereophile (kind of technical). Also reference pages 26-28 in the "b" version amp manual, paying particular attention to sections T5.4.4 and T5.5

High quality properly constructed and terminated 50 Ohm cables are all you should need for great sound. No fancy platinum, air dielectric, etc.

Here is one 50 Ohm cable I'll be trying from L-Com- 18 awg solid silver coated copper with 2 silver coated copper braids for shielding. Wide bandwidth and extremely cheap- no loss in trying them.

Thanks Fsarc. You obviously have had way too much education in the reading area. You seem competent in the reading comprehesion area too.

What's you take on the differences with BNC connectors of coax, the L-Com cable and a very high quality copper cable?

Your thoughts?

Jeff Rowland used to advocate matching input and output impedances with his amps and preamps. He maintained that 600 ohms at both ends allowed for a better transfer of signal. If that's true, then is it the BNC, the 50 ohms value or simply having the same impedance at each end the primary cause for the improved sound quality?