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MDAC First Listen (Part 00101010)

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Audio over Ethernet

https://en.wikipedia.org/wiki/Audio_over_Ethernet

I last searched for this a year so ago. I only did a quick search now to find this link. Please feel free to continue the research.

Jirij, you'll interpret it far better than me anyway (thanks ;))

IIRC the protocols are specific to an audio application and there are 2 common (commercial?) protocols, so not a "standard" part of a PC configuration or general purpose network.

So it's quite right that John is concentrating on DAC design above interface protocols, and concentrating on optimising the interfaces that are already common.

Possibly the bespoke interface which will connect fdacs together (have I remembered this correctly?) will allow alternative external interface modules to be implemented in the future? but that isn't part of the current design objectives to create a statement design based around "conventional" interfaces

No apologies if I've remembered or interpreted any of this incorrectly.
 
davidjt said:
You know the rules: no subjective impressions allowed. :mad:
Click to expand...

We would never get agreement on any proposed 'guessing' protocol that would suffice here....suggest we use an atomic clock ecorporating relativistic corrections to measure this timming out issue and then deal with it.:D
 
Well I've started ordering components for the Detox prototype :) But I'm not feeling 100% today so have not worked on the schematic / PCB design as I'd hope.

I have been thinking about the circuit design around the Clock / Clock-lock interface / Spread Spectrum noise modulator... these circuits blocks are the core of the design :) - the USB Hubs themselves are easy...
 
BigDog said:
You've got my attention and 50 GBP!

Will be interesting to see what the eye patterns look like with DETOX!
Click to expand...

Welcome to the Detox project :) Thank you for your support.

It will be an interesting challenge to measure the LF noise directly on the USB data stream - hopefully once the new test system arrives (its still not been shipped:( ) it will make the task easier.... lets see :)
 
ChrisPa said:
Audio over Ethernet

https://en.wikipedia.org/wiki/Audio_over_Ethernet

I last searched for this a year so ago. I only did a quick search now to find this link. Please feel free to continue the research.

Jirij, you'll interpret it far better than me anyway (thanks ;))

IIRC the protocols are specific to an audio application and there are 2 common (commercial?) protocols, so not a "standard" part of a PC configuration or general purpose network.

So it's quite right that John is concentrating on DAC design above interface protocols, and concentrating on optimising the interfaces that are already common.

Possibly the bespoke interface which will connect fdacs together (have I remembered this correctly?) will allow alternative external interface modules to be implemented in the future? but that isn't part of the current design objectives to create a statement design based around "conventional" interfaces

No apologies if I've remembered or interpreted any of this incorrectly.
Click to expand...

As I already mentioned Swiss co Merging Technology make professional recording studio gear and a new DAC based on Ethernet:

This uses the RAVENNA protocol that Merging Technologies helped to develop for high sampling rate applications and allows very robust and accurate transfer of the digital audio data from the computer to NADAC. The data is stored in a large buffer memory in the NADAC and then clocked out by the unit’s precision internal clock. This and the RAVENNA protocol’s ultra-stable Precision Time Protocol (IEEE 1588) eliminates the cable and jitter related problems associated with conventional digital audio interfaces.

So maybe Ethernet will be the next big thing in audio, who knows, but as others have noted designers will probably have to deal with the same secondary RF effects as USB using PC noise generators as a music source :p As most of us rely on USB Detox may be a winner!

JohnW do you think BigDog will benefit from a Detox given he already has galvanic isolation and is about to remove USB +5V?

Re #5: I am using an Adnaco-S3B: USB 3.0/2.0/1.x Over Fiber Optic Extension System to provide galvanic isolation between my PC music server and DAC. However, since my DAC is self-powered and does not need to “see” the +5V, I defeat the +5V normally supplied by the Adnaco receiver to a DAC.
 
JohnW said:
Welcome to the Detox project :) Thank you for your support.

It will be an interesting challenge to measure the LF noise directly on the USB data stream - hopefully once the new test system arrives (its still not been shipped:( ) it will make the task easier.... lets see :)
Click to expand...

Hope you are feeling better, John.

You mentioned clocklock of the DETOX with the MDAC / FDAC but not with other brand DACs.
Would there be any downside with the presence of the clock with other DACs?

Got to thinking about how the DETOX will dock with my DAC. I think I saw in an earlier post that you were planning to use a rigid USB adapter to avoid using a cable.
What are you expecting the dimensions of the DETOX case to be, particularly the side where the adapter will go?
Want to see how this might work since like most DACs, mine is a bit congested with other jacks close to the USB2.0.
 
jamjar784 said:
JohnW do you think BigDog will benefit from a Detox given he already has galvanic isolation and is about to remove USB +5V?

Re #5: I am using an Adnaco-S3B: USB 3.0/2.0/1.x Over Fiber Optic Extension System to provide galvanic isolation between my PC music server and DAC. However, since my DAC is self-powered and does not need to “see” the +5V, I defeat the +5V normally supplied by the Adnaco receiver to a DAC.
Click to expand...

Its a good question, I think BigDog with his Fiber Optic Extension System has a very good system.

The Optical link will remove the PC's RF and Ground loops - two really big issues, and don't forget that the Detox is not galvanically isolated on its USB2.0 output.

The question is what is the jitter spectrum like from this card? - it has the potential to be good as its isolated from the PC's processing effects and other noise - hard to say... They are never designed to be low noise, but atleast its starting from a far better position!

Its certainly true that BigDog will benefit far lass from using the Detox then other users as he already has a decent USB solution... But I can only say this from afar, I have no direct experience.... It will be interesting to hear back from BigDog once he tries the Detox in his system.
 
BigDog said:
I am not receiving email notifications of posts to the forum as I selected in the Forum Tools for this thread.
Since I am on the edge of my seat with anticipation of each and every reply ;-),
I sign on frequently to see what's new.
Click to expand...

Follow up to original post: Signed in this morning and found numerous posts for which I did not receive email notification.
Typically on forums when you are already subscribed to a thread and click on FORUM TOOLS, it will have an option to UNSUBSCRIBE. I do not see this message but do see SUBSCRIBE TO THIS FORUM. When I select this option, it asks for selection of notification, which in my case is INSTANT EMAIL NOTIFICATION but this is not happening.

Thanks.
 
BigDog said:
Hope you are feeling better, John.
Click to expand...

Thanks, back working :)

BigDog said:
You mentioned clocklock of the DETOX with the MDAC / FDAC but not with other brand DACs.
Would there be any downside with the presence of the clock with other DACs?
Click to expand...

There is no "downside" to having the Clock Lock circuit in the Detox, the switch removes the Clock Lock circuit from the internal signal path when not required.

BigDog said:
Got to thinking about how the DETOX will dock with my DAC. I think I saw in an earlier post that you were planning to use a rigid USB adapter to avoid using a cable.
What are you expecting the dimensions of the DETOX case to be, particularly the side where the adapter will go?
Want to see how this might work since like most DACs, mine is a bit congested with other jacks close to the USB2.0.
Click to expand...

I'm not advocating a solid USB link as the Detox with its soild RF screening will be heavy, I cannot recommend "hanging" it off the rear of a DAC's USB socket.

I "believe" the thinking of the ReGen was to design to be as small and a light as possible so it could be safely hung of the rear a DAC - but to achieve this the designers had no choice but to limit the designs potential (limited PSU filtering, not the greatest clock, no RF filtering etc).

You have to weigh the Pros and Cons of these limitation - while a direct connection is "nice" IMO better RF & PSU filtering is more important.
 
BigDog said:
Follow up to original post: Signed in this morning and found numerous posts for which I did not receive email notification.
Typically on forums when you are already subscribed to a thread and click on FORUM TOOLS, it will have an option to UNSUBSCRIBE. I do not see this message but do see SUBSCRIBE TO THIS FORUM. When I select this option, it asks for selection of notification, which in my case is INSTANT EMAIL NOTIFICATION but this is not happening.

Thanks.
Click to expand...

This does not surprise me as I believe that the notification service can be quite slow, my experience from other forums is that its not "instant"..... its more for people in a slower lane :) who are interested in "daily" updates then minute by minute news...
 
JohnW said:
I'm not advocating a solid USB link as the Detox with its soild RF screening will be heavy, I cannot recommend "hanging" it off the rear of a DAC's USB socket.

I "believe" the thinking of the ReGen was to design to be as small and a light as possible so it could be safely hung of the rear a DAC - but to achieve this the designers had no choice but to limit the designs potential (limited PSU filtering, not the greatest clock, no RF filtering etc).

You have to weigh the Pros and Cons of these limitation - while a direct connection is "nice" IMO better RF & PSU filtering is more important.
Click to expand...

OK, that works. I will use my USB cable with defeated +5V between DETOX and DAC.
Will DETOX need to see +5V from the PC, etc., to function like some DACs?

Thanks for your continuing patience and tutelage.
 
JohnW said:
This does not surprise me as I believe that the notification service can be quite slow, my experience from other forums is that its not "instant"..... its more for people in a slower lane :) who are interested in "daily" updates then minute by minute news...
Click to expand...

For whatever reason, have been getting almost instantaneous notifications of posts today.

Maybe less traffic today since others may have taken Sunday off! ;-)
 
BigDog said:
in my case is INSTANT EMAIL NOTIFICATION but this is not happening.
Thanks.
Click to expand...

Given that there are posts roughly every 30 minutes, why do you need notification?

This thread has been running for many years, possibly the longest audio thread ever!

Some notification systems only send notification after you have logged in to the last one.
 
JohnW said:
Thanks, back working :)



There is no "downside" to having the Clock Lock circuit in the Detox, the switch removes the Clock Lock circuit from the internal signal path when not required.



I'm not advocating a solid USB link as the Detox with its soild RF screening will be heavy, I cannot recommend "hanging" it off the rear of a DAC's USB socket.

I "believe" the thinking of the ReGen was to design to be as small and a light as possible so it could be safely hung of the rear a DAC - but to achieve this the designers had no choice but to limit the designs potential (limited PSU filtering, not the greatest clock, no RF filtering etc).

You have to weigh the Pros and Cons of these limitation - while a direct connection is "nice" IMO better RF & PSU filtering is more important.
Click to expand...

Subject to the relative positions of the sockets you could always support the Detox so that it was at just the right height for a rigid connector.
 
iansr said:
Subject to the relative positions of the sockets you could always support the Detox so that it was at just the right height for a rigid connector.
Click to expand...

Like a plywood shelf with a support block to the rear?

I know someone who can do that :D:D
 
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