Users of the AES/EBU input and cables

[Mikeeo]

I'm no expert on this subject but that seems a bit of a disappointing reply from Devialet.

Without doubt, they initially said that RCA to AES/EBU was the preferred Master/Companion connection (over RCA/RCA); though latterly this appears to have been compromised by them shipping an RCA/RCA cable with 400s and 800s.

So the answer should be either "there is no sonic compromise connecting a standard RCA output to a standard AES/EBU input in the digital domain" or "there would be a sonic compromise with such a connection but the appropriate correcting circuitry is triggered by the configurator when you specify an RCA to AES/EBU connection" or "you should only use RCA to RCA for optimum sound quality".

But if, as is inferred, the AES/EBU input is strictly 110 ohms are all times (and presumably the RCA output is strictly 75 ohms at all times) then, at least in relation to a short cable length of 0.5m or so, my understanding is that it does not matter whether the cable is 75 ohms or 110 ohms - because any compromises will be just the same.

If the source and destination impedances are unmatched, some of the energy being transferred from source to destination is reflected back from the destination (or wherever there is an impedance mismatch in the connecting circuit (cable), whether that connecting circuitry (cable) is 75 ohms or 110 ohms) towards the source. Presumably such reflections could cause echoes, or cause signals at certain frequencies to be reduced through cancellation.

So, Mike, my understanding is that it makes no difference whether you use 75 ohm or 110 ohm cable - but my understanding now is that I do not know whether the initial recommended connection is 100% ok or is compromised!

What us slightly eccentric folk need to know is whether it is worth spending €260 on a bit of audioprana cable or whether we would be better buying 20 or 30 more CDs.

Ian,

That was good thoughtful comments that made me think again. I am as well no expert in this area and is just learning by doing. If someone here has a more in-depth knowledge in this area, specially digital cables and implementation of 75 or 110 ohm applications please step forward.
I would for sure like know how a 110 ohm cable will be the deciding factor for the recognition at the AES/EBU side!?

I think, in a mission to turn into a lifestyle manufacturer Dev just took an easy road with the RCA-RCA link, not to complicate too much for the user as otherwise would have to order a tailored semi-balanced 75 or 110 ohm RCA-XLR.

I told Thierry by the way about my view concerning the supplied Crystal linking cable. He was surprised!!!? The comment to defend the cable was that it was quite expensive, WTF! Honestly, most of us know that it is not always money that solves the quality HiFi issue.

The reflection issue is what worries me the most so perhaps the Audioprana or my own construction with a Lundahl 75/110 ohm transformer will be the best solution?

With or without the 75/110 ohm conversion Audioprana supplies it may just be a very good cable anyway. We have to wait for the Audioprana users to report back.

As the application always will be 'semi' due to a single ended to balanced connection I would for sure like to know if the cable impedance would decide the input recognition or if it does not matter!? Or it would be better to use a 75/110 transformer!?
Thierry says the AES/EBU inputs are strictly normal transformer driven 110 ohm and that there is no 'impedance' converter or such gizmo.

So it is up to us eccentric suckers (include me please) to do the real life testing. I will curiously monitor others findings, so keep on exploring, please!

Trust your ears and cheers/Mike