Users of the AES/EBU input and cables

[Mikeeo]

Hi,

I bring this message from the Devialet 400 & 800 forum as I thought it would be of interest to you who would like to connect your mono units or dig signal in to the AES/EBU input.

From my conversation with Thierry at Devialet:

"News flash!

Just had a talk to Thierry about the linking cable and the RCA--XLR connection between Master and Companion.

There is no setting for the AES/EBU input not even when configured for linking RCA--XLR. The AES/EBU input is strictly 110 ohm at all times.

So I asked Thierry how this could work then!

He says (which I didn't manage to read on the homepage) that when using the RCA--XLR link the linking cable should be 110 ohms and not 75!!! As the system will recognize the impedance of the cable. And this goes for all of us that would like to use the AES/EBU for a streaming input on the Master as well ie use a 110 ohm cable.
Connection is the 'semi-balanced' way as schematically showed on Devs homepage.

I told him about the Audioprana cables and the 75/110 ohm transformation. Thierry said it would not be a problem but less good as their own solution due to adding another transformer in the line of signal.

Strange that they do not mentioning this?

Well, I am ordering some 110 ohm diy cable. Any suggestions for a good one?

Cheers/Mike"

[mauidan]

Hi,

I bring this message from the Devialet 400 & 800 forum as I thought it would be of interest to you who would like to connect your mono units or dig signal in to the AES/EBU input.

From my conversation with Thierry at Devialet:

"News flash!

Just had a talk to Thierry about the linking cable and the RCA--XLR connection between Master and Companion.

There is no setting for the AES/EBU input not even when configured for linking RCA--XLR. The AES/EBU input is strictly 110 ohm at all times.

So I asked Thierry how this could work then!

He says (which I didn't manage to read on the homepage) that when using the RCA--XLR link the linking cable should be 110 ohms and not 75!!! As the system will recognize the impedance of the cable. And this goes for all of us that would like to use the AES/EBU for a streaming input on the Master as well ie use a 110 ohm cable.
Connection is the 'semi-balanced' way as schematically showed on Devs homepage.

I told him about the Audioprana cables and the 75/110 ohm transformation. Thierry said it would not be a problem but less good as their own solution due to adding another transformer in the line of signal.

Strange that they do not mentioning this?

Well, I am ordering some 110 ohm diy cable. Any suggestions for a good one?

Cheers/Mike"

Already gave you a suggestion in the Master/slave link thread:
http://www.partsconnexion.com/wire_interc_connex.html

I use a Audience Au24 SE cable between my PS Audio PWT and master.

I could get Audience to make me a SPDIF RCA to XLR cable based on Devialet's schematic, but IMO, it's total waste of time and money.

You still have a 75 ohm output trying to drive a 110 ohm cable/input.

[Mikeeo]

Hi,

I bring this message from the Devialet 400 & 800 forum as I thought it would be of interest to you who would like to connect your mono units or dig signal in to the AES/EBU input.

From my conversation with Thierry at Devialet:

"News flash!

Just had a talk to Thierry about the linking cable and the RCA--XLR connection between Master and Companion.

There is no setting for the AES/EBU input not even when configured for linking RCA--XLR. The AES/EBU input is strictly 110 ohm at all times.

So I asked Thierry how this could work then!

He says (which I didn't manage to read on the homepage) that when using the RCA--XLR link the linking cable should be 110 ohms and not 75!!! As the system will recognize the impedance of the cable. And this goes for all of us that would like to use the AES/EBU for a streaming input on the Master as well ie use a 110 ohm cable.
Connection is the 'semi-balanced' way as schematically showed on Devs homepage.

I told him about the Audioprana cables and the 75/110 ohm transformation. Thierry said it would not be a problem but less good as their own solution due to adding another transformer in the line of signal.

Strange that they do not mentioning this?

Well, I am ordering some 110 ohm diy cable. Any suggestions for a good one?

Cheers/Mike"

Already gave you a suggestion in the Master/slave link thread:
http://www.partsconnexion.com/wire_interc_connex.html

I use a Audience Au24 SE cable between my PS Audio PWT and master.

I could get Audience to make me a SPDIF RCA to XLR cable based on Devialet's schematic, but IMO, it's total waste of time and money.

You still have a 75 ohm output trying to drive a 110 ohm cable/input.

Mauidan,

Thanks, the link was noticed and I've ordered from them a few times.

According to Devialet the 75 ohm impedance is not the main driving force (or signal quality deciding factor) for the AES/EBU input but the 110 ohm cable. I can only go for that which I will.

I will let you know if it was a waste of T&M as I will def give it a go.

Best/Mike

[IanG-UK]

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.

[rwjr44]

Acoustic Zen's Absolute 110 Digital cable. They will configure to your specifications. Expensive (IMHO)

[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

[mauidan]

Why don't you get one of these:

http://www.fullcompass.com/product/397815.html

and borrow a AES/EBU cable and see how it sounds.

BTW, I agree with Thierry, if the Devialet's AES/EBU inputs are transformer coupled, you don't need a impedance converter.

Wish Devialet had installed BNC connectors for this link.

[Pim]

Interesting to read that no-one here seems to know that the RCA connector itself isn't 75 Ohm at all. There's a bit written about it on the Blue Jeans cable web site (sorry, due to the slow internet here at work I can't open it to copy a link) From what I remember reading the RCA connector has the wrong inside and outside diameters to make it true 75 Ohm. They sell a Canare connector that's built to be as close to 75 Ohm but not right there. So the real question here should be; What impedance is an RCA connection?

This brings me to the Crystal Cable. It's definitely NOT a 75 Ohm cable looking at the size of it so without hearing it i would say it sells on the 'enormous change in the sound it makes' when all it really does is loose ones and zeros because of the impedance mismatch on both sides of the cable. And maybe that's why some on this forum have had better results with 'true 75 Ohm' cable (or near enough)

[mauidan]

Interesting to read that no-one here seems to know that the RCA connector itself isn't 75 Ohm at all. There's a bit written about it on the Blue Jeans cable web site (sorry, due to the slow internet here at work I can't open it to copy a link) From what I remember reading the RCA connector has the wrong inside and outside diameters to make it true 75 Ohm. They sell a Canare connector that's built to be as close to 75 Ohm but not right there. So the real question here should be; What impedance is an RCA connection?

This brings me to the Crystal Cable. It's definitely NOT a 75 Ohm cable looking at the size of it so without hearing it i would say it sells on the 'enormous change in the sound it makes' when all it really does is loose ones and zeros because of the impedance mismatch on both sides of the cable. And maybe that's why some on this forum have had better results with 'true 75 Ohm' cable (or near enough)

That's why I posted:

"Wish Devialet had installed BNC connectors for this link."

Interesting that you can tell how the Crystal Cable performs just by looking at.

[Pim]

Interesting to read that no-one here seems to know that the RCA connector itself isn't 75 Ohm at all. There's a bit written about it on the Blue Jeans cable web site (sorry, due to the slow internet here at work I can't open it to copy a link) From what I remember reading the RCA connector has the wrong inside and outside diameters to make it true 75 Ohm. They sell a Canare connector that's built to be as close to 75 Ohm but not right there. So the real question here should be; What impedance is an RCA connection?

This brings me to the Crystal Cable. It's definitely NOT a 75 Ohm cable looking at the size of it so without hearing it i would say it sells on the 'enormous change in the sound it makes' when all it really does is loose ones and zeros because of the impedance mismatch on both sides of the cable. And maybe that's why some on this forum have had better results with 'true 75 Ohm' cable (or near enough)

That's why I posted:

"Wish Devialet had installed BNC connectors for this link."

Interesting that you can tell how the Crystal Cable performs just by looking at.

I can't. But what I can see is a cable constructed so thin it cannot possibly be 75 Ohm unless they used some very special dielectric insulator (around the inner core). The impedance is directly related to the size and material of the inner core.

I've done a few years in antenna and satellite installation and that gives you a bit of insight into all this. I don't claim to be an expert but a few things are clear; Digital satellite signal goes into the Giga Hertz and runs without any problem or interference through a $1.50/m solid core quad cable over 30m or more. Attenuation isn't an issue, nor is interference from outside. That same cable does an equally good job at transferring analog tv signal which is in the Mega Hertz. I don't know at what frequency digital audio runs but I guess it's somewhere in between.(700Mb on a disc, running for an hour. Not sure how to do the maths but near enough) I just can't see how something as complicated as a digital video signal can be transferred through ordinary coax without any issues but when it is an audio signal suddenly we need hyper expensive super duper cable. I guess if you were trying to sell a very expensive video cable and show your customer the 'difference' in your shop and they can't see any they will tell you your full of it. It's because with hearing it is harder to tell that 'difference' (move your head an inch of two and the sound is different so is it you or is it the cable) that people fall for expensive cables.

Devialet has shown the world that you don't have to spend mega bucks to get a great sounding amp. Surely there is a minute possibility that you can get equally great sound with a well constructed coax cable that doesn't cost a fortune?

Nearly forgot. I agree; BNC would have been great!