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MDAC First Listen (Part 00101010)

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jirij

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Jiri:

I wasn't advocating that John should incorporate a dlna client in FDAC. I understand his situation. And I certainly would not expect him to develop his own protocols. I was just responding to the implication that USB is all we have and that ethernet-based systems are complex to setup. Mine is simple, works well, and sounds good.

- Richard.
I agree that as a "non-reference" or secondary setup it's great. But, technogically, it's comparable to WiFi/Bluetooth streaming or Adaptive USB as it has (AFAIK) no feedback channel, making the "master" DAC clock basically useless without a big buffer (and multi-second latency).
I was mostly replying to the idea of replacing USB with Ethernet (or network streaming), sorry if that wasn't your point.

Including a DLNA client in the MDAC2 / FDAC wouldn't actually be that hard - there are SoC modules that (similarly to wifi/bluetooth) take care of most of the stuff, but it's again not a "better" replacement for USB.

edit: Well, technically, the DAC you could use TCP's congestion control to throttle the bandwidth, but it couldn't achieve the low latencies USB (with a feedback channel) can.
 
(And the best part is that Ethernet doesn't even get you the benefits some here preach - compared to USB, it only breaks the DC path, all the nasty RFI and jitter are still there!)

None of the above says that it's impossible or that USB is technologically better - it's simply much easier to use in the existing software ecosystem.

I could not agree more!!! I could not sum it up better!
 
Yes, I understand - we all do this - judge the messenger, not the message but in matters of science & technology we are meant to use our logic more than our emotions - that is the theory but practise is often different to this

Errr, you missed my point.
 
I can understand that you would like your optimized computer to sound better. Because you have spend a lot of time and money on it.


If the Detox can solve the problem for JW's average noisy PC, then it is completely irrelevant and a waste of time to look at how a optimized PC sound/measure. Because there will be no difference.

If the Detox can achieve this then I would consider it a game changer or the holy grail of computer audio :cool:

Yup - see my earlier post about the Detox's potential to level the hardware playing field in computer audio.
 
Your confidence in John's capabilities and, as someone else noted, his non-BS approach is reassuring...much like my opinion of Nelson Pass after doing business with him for 30+ years.

That being said, I believe that "In God we trust, all others bring data".

I see from the referenced DETOX description that it is a series of 3 USB hubs(?) which are daisy chained with 3 RF filters. IF I understand correctly, the USB hubs regenerate the USB data, not unlike the REGEN.

Unless there is proprietary information involved, to reiterate, is there a reason why the DETOX might be preferred?

As it happens I'm also a NP fan - I've had several of his amps in the past. The common theme is that there good reason to hold what both these designers do in high regard.
 
Well, that's not strictly true. It's not fundamentally different to USB. Data integrity is no problem, but clearly the reciever circuitry has the potential to cause secondary issues for the dac. Rf noise, supply noise, ground plane modulation etc.

All can be designed around.

I agree :)
 
Errr, you missed my point.

OK, no problem ( I do understand the point about John's reputation & your belief in what he says)!
Many others have said that "secondary effects" are part & parcel of connections to computers for audio purposes
Many others have said that low frequency jitter is important
Many others have said that they hear a difference between Flac & WAV
Many others have said that Ethernet & WiFi can have more issues than USB

It's really a matter of a person's perception of who is saying it as to the efficacy/reception/acceptance of the message
I believe you agreed with me on this point already? - we mostly come to very quick decisions through the non-logical part of the brain & then proceed to rationalise the answer we have already decided? This is not supposed to be the approach with discussions in science or technology but it often is
 
I agree that as a "non-reference" or secondary setup it's great. But, technogically, it's comparable to WiFi/Bluetooth streaming or Adaptive USB as it has (AFAIK) no feedback channel, making the "master" DAC clock basically useless without a big buffer (and multi-second latency).
I was mostly replying to the idea of replacing USB with Ethernet (or network streaming), sorry if that wasn't your point.

I'm not sure what you mean in this context by "non-reference". Doesn't it depend on the design of the client? Are you saying that, inherently, all dlna solutions are always inferior to USB?

In my setup the MDAC has the possibility of either an optical link or spdif to the dlna client's digital output. I usually use spdif because the optical is limited to 24/96.

- Richard.
 
How will you see our replies then ? :confused:
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.
 
As it happens I'm also a NP fan - I've had several of his amps in the past. The common theme is that there good reason to hold what both these designers do in high regard.

I have run NP amps in my system continuously since the '80s...SA3->SA2's->Aleph2's->Aleph1.2's->XA160's currently.

Not being familiar with JohnW's work, I will defer to the opinions expressed here but look forward to getting to know him.
 
I have run NP amps in my system continuously since the '80s...SA3->SA2's->Aleph2's->Aleph1.2's->XA160's currently.

Not being familiar with JohnW's work, I will defer to the opinions expressed here but look forward to getting to know him.

I had a pair of Aleph 2's at one point and more recently a pair of FW F4s. I've no doubt the XAs are really good. I suspect the FW SIT monoblocks are his finest yet, if you have 8 ohm / efficient speakers. However, my expectations for John's VFET monoblocks are very high indeed . . .
 
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.

Also, just now after composing a lengthy response to a post, I hit SUBMIT REPLY and the system told me I was NOT signed on and I lost the content of my reply.
Language barrier? :-D
 
I'm not sure what you mean in this context by "non-reference". Doesn't it depend on the design of the client? Are you saying that, inherently, all dlna solutions are always inferior to USB?
Well, yes and no. :)

First, DLNA is just a set of some guidelines, sets of protocols to use for certain operations, a single name for which a device can be "certified", a nice label on a device. These are AFAIK not freely available and can evolve over time, changing some protocols for other ones.
Last time I measured a device, it used RTSP messages with RTP/RTCP for the actual stream itself. The RTP RFC mentions sender reports (SR) and receiver reports (RR), but those don't seem to provide any way to control the replay rate on the server. In fact, the "Congestion Control" section mentions the "inelasticity" more closely.
To be honest, I don't know whether there's an implementation that utilizes the RR messages to throttle the server down (or speed it up), maybe such implementation extends the field definitions as per section 6.4.3, maybe the extension is specified somewhere in the DLNA guidelines, or maybe not.

This only highlights the issue at hand - streaming protocols with so much abstraction and related control channels (think RTSP) are simply too much disconnected from what the source is and often presume it's an existing stream of a given rate, which cannot be slowed down or sped up (although there's a RTSP message type for that, but it's meant for user control, ie. 2x speed for funny voices).

Also, due to its network nature and also due to the fact that DLNA presumes any related media to be streamed through the same path (ie. video alongside audio), there is going to be decent buffering, at least few tens of milliseconds, likely more given bigger RTT (I believe RTSP/RTP has a detection for that). Not counting overhead of underlying protocols (ie. ARP cache invalidation events on L2).

In the end, all of this is huge, HUGE overhead over what USB does so efficiently and natively. Given its very fast device response times, the buffer can be much smaller, which allows you to ie. watch a youtube video on the screen and play the music/sounds via the "sound card" with nearly perfect "lip sync". (It also has its advantages when recording / tracking.)

So is DLNA inferior to USB? That really depends on the use case. From the point of view of a "typical" hifi user, who presses the play button and goes away to sit in a comfortable armchair, probably not so much. The other use cases really depend on whether DLNA somehow implements the USB-like "feedback" channel - if not, it's basically equivalent to Adaptive USB. My bet goes this way - if I've learned anything from cheap chinese SoCs, it's that they always go for the least effort solution. (Looking at you, Broadcom, how dare you not support TLS1.0!).

Jiri :)
 
The Detox works on "cleansing" the USB Data on various levels:-

1. RF filters the incoming Data, between cascaded USB stages & on the final outputs.

2. Each USB Hub stage adds its own Jitter attenuation, clock from the SAME reference clock so that you don't have "beating" between USB clock domains.

3. Clock lockable to the MDAC / FDAC audio Master clock via the DAC clock output - this insure the USB clock in the Detox and MDAC / FDAC are synchronised - eliminating unwanted clock beating effects.

4. A Spread spectrum mode is selectable that adds random white noise to the clock to decorrelate the remaining phase noise spuire.

5. Provides a Clean low noise USB power to the DAC (important for the FDAC whose Galvanically isolated USB input stage is powered via the USB host device).

6. Two USB Outputs:- The first is a galvanically isolated USB1.1 (12Mpbs) and the second output supports full High speed 480Mbps USB 2.0.

7. Supplied with a simple linear AC mains adaptor.

Thanks for the detailed DETOX description, John. Much appreciated but do have a few follow up questions…
Re #3: How would this clock work with DACs other than the MDAC / FDAC?

Re #4: Am I correct to assume that this is a listener preference setting?

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.
Would I defeat the +5V supplied by the DETOX similarly?
 
Thanks for the detailed DETOX description, John. Much appreciated but do have a few follow up questions…

Re #3: How would this clock work with DACs other than the MDAC / FDAC?

You cannot synchronously clocklock the Detox USB to other DAC's - its an advance feature for MDAC / FDAC owners.

The synchronously clocklocking Detox USB interface is 'Icing on the cake" its the correct way of doing things if you have the option - but for other DAC's without a clocklock interface you will still gain the other benefits of the Detox.

Re #4: Am I correct to assume that this is a listener preference setting?

Yes, via toggle switch.

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.

Would I defeat the +5V supplied by the DETOX similarly?

Yes, you can do - best via a modified USB lead.
 
You cannot synchronously clocklock the Detox USB to other DAC's - its an advance feature for MDAC / FDAC owners.

Is there any downside of the DETOX clock for us other DAC users?

Yes, via toggle switch

Nice!

Yes, you can do - best via a modified USB lead.

Any downside to not defeating?
My first try was with a bit of electricians tape but plan on DIY purpose built USB w/o +5V conductor.

You've got my attention and 50 GBP!

Will be interesting to see what the eye patterns look like with DETOX!
 
Thanks, misterdog. FWIW, how much time on the clock?

IF I get wordy ;-), will just compose offline then Copy/Paste.

Not sure about the time limit myself...misterdog I guess will know....but try going back and forth on your browser if you get timed out, sometimes this recovers your hard thought out text and you can then copy and paste it after you log back in....your belt and braces approach of off-line composition would be safest.
 
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