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Old 5th April 2011, 02:11 PM   #271
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I am curious to why not those that have received and evaluated the exaU2I are writing about their experiences here??

Have all the exaU2I units been sold to competitors of exaDevices

I cannot be the only one that have managed to connect the exaU2I and have it running as I now have connected it to several DAC in several ways and it have worked every time without any issues...
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Old 5th April 2011, 03:16 PM   #272
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Default Tweaking of the exaU2I...

Since the exaU2I are a DIY product I have made an easy to change / modify setup and I have tweaked the exaU2I in several ways just to check if the already excellent performance of the standard product can be tweaked further.

The attached pictures are some days old and I have since then reconfigured and are evaluating other "upgrades".

The setup in the pictures have a Corian base and top and the 5 volt USB voltage are disconnected and the FPGA, clocks, GMRs and LVDS are powered by LIFEPO4 battery.

The difference in fidelity between the standard exaU2I and the tweaked exaU2I (pictured) and the current tweaked exaU2I are not very big as the standard unit performs excellent.
For me every little improvement are of importance and my setup will be tweaked until there is no more to gain
Attached Images
File Type: jpg exaU2I eval II-1.jpg (195.3 KB, 421 views)
File Type: jpg exaU2I eval II-2.jpg (194.4 KB, 396 views)
File Type: jpg exaU2I eval II-3.jpg (197.6 KB, 396 views)

Last edited by RayCtech; 5th April 2011 at 03:20 PM.
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Old 5th April 2011, 04:07 PM   #273
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Originally Posted by RayCtech View Post
In my setup the differences are easily detected and the exaU2I stays connected to the NEC USB 3.0 controller

This is certainly wonderful but can you suggest any reasons why an async, galvanically isolated device should be sensitive to the type of interface. I also tried async usb with the vain hope that it will eliminate cable and port effects but it appears every bit as sensitive as the old 2707 isochronous chip.
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Old 5th April 2011, 05:00 PM   #274
NicMac is offline NicMac  Italy
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Quote:
Originally Posted by RayCtech View Post
I am curious to why not those that have received and evaluated the exaU2I are writing about their experiences here??
Maybe you have the only one
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Old 5th April 2011, 05:09 PM   #275
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Originally Posted by analog_sa View Post
This is certainly wonderful but can you suggest any reasons why an async, galvanically isolated device should be sensitive to the type of interface. I also tried async usb with the vain hope that it will eliminate cable and port effects but it appears every bit as sensitive as the old 2707 isochronous chip.
I believe the answer may simply be "noise" of all kinds.
Of course there are also many other issues that will have impact,
but reducing noise in power supplies and reducing the noise the power supplies sends back to the mains have always improved my setups.
I have never been able to reach a level where the improvements stops...
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Old 5th April 2011, 05:21 PM   #276
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Maybe you have the only one
That statement are already proven wrong as I now have two exaU2I here The second unit belongs to a friend and I am connecting it up to his DAC with the balanced LVDS over HDMI interface for him.
It was very convenient that he also had ordered one unit as I now easily can compare different configurations...
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Old 5th April 2011, 06:13 PM   #277
Raj1 is offline Raj1  United Kingdom
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Originally Posted by RayCtech View Post
I believe the answer may simply be "noise" of all kinds.
Of course there are also many other issues that will have impact,
but reducing noise in power supplies and reducing the noise the power supplies sends back to the mains have always improved my setups.
I have never been able to reach a level where the improvements stops...
You could try shunt regulating the 3.3V and 1.2V feeds to the NEC chip if you really want to go to the nth degree - I am thinking of doing this at some point.
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Old 5th April 2011, 11:04 PM   #278
rsdio is offline rsdio  United States
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Originally Posted by Marek View Post
I can't understand why you guys talk about FW again and again. From technical point of view there is no difference what kind of interface you use - USB, FW, Ethernet, Bluetooth etc. The fact that pros use FW has nothing to do with level of output jitter.
If you want FW because you like this name or you like to feel like pro because you use the same interface go ahead but this won't give you nothing more than that. Understand it.
If you disagree post firm advantages of FW or leave this FW talk.
You are correct that there are not necessarily any electronic advantages of FW over USB. However, the ability to use standard drivers limits the choices. An electrical interface must have standards available for audio which meet the needs of the interconnect. Ethernet would work, too, but ethernet does not specifically define an audio standard for transport. USB and FW do have such protocols, but USB-Audio has too many variations, and the ones needed are missing from Windows. FW has had isochronous audio protocols since the beginning, so the combination of electrical and protocol compatibility makes FW unique. Unfortunately, I suppose Windows has poor support for FW, too. But in those situations where FW is supported, there is a much lighter load on the operating system to support streaming audio - and this is another advantage of FW over USB.

We should probably start another topic if FW becomes a popular side-subject.

Last edited by rsdio; 5th April 2011 at 11:08 PM.
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Old 6th April 2011, 10:11 AM   #279
Marek is offline Marek  Poland
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Originally Posted by rsdio View Post
You are correct that there are not necessarily any electronic advantages of FW over USB. However, the ability to use standard drivers limits the choices. An electrical interface must have standards available for audio which meet the needs of the interconnect. Ethernet would work, too, but ethernet does not specifically define an audio standard for transport. USB and FW do have such protocols, but USB-Audio has too many variations, and the ones needed are missing from Windows. FW has had isochronous audio protocols since the beginning, so the combination of electrical and protocol compatibility makes FW unique. Unfortunately, I suppose Windows has poor support for FW, too. But in those situations where FW is supported, there is a much lighter load on the operating system to support streaming audio - and this is another advantage of FW over USB.

We should probably start another topic if FW becomes a popular side-subject.
My knowledge about FW audio support is poor but as you said FW has isochronous mode defined which is not what we want. In isorchonous mode data source (PC) is a clock master like with PCM270x. If we want achieve lowest possible jitter , clock source (precise low jitter XO) should be located close to DAC and this requirement is the main reason for creating exa2UI.
I do not know FW solutions you talking about but I'm not sure it offers best best jitter performance which we want here.
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Old 6th April 2011, 11:05 PM   #280
rsdio is offline rsdio  United States
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Originally Posted by Marek View Post
My knowledge about FW audio support is poor but as you said FW has isochronous mode defined which is not what we want. In isorchonous mode data source (PC) is a clock master like with PCM270x. If we want achieve lowest possible jitter , clock source (precise low jitter XO) should be located close to DAC and this requirement is the main reason for creating exa2UI.
I do not know FW solutions you talking about but I'm not sure it offers best best jitter performance which we want here.
Sorry, but isochronous has many different meanings. In the case of FireWire, isochronous merely means dedicated audio bandwidth, which is different from FireWire disks which only get bandwidth when it is available.

Rest assured that FireWire audio interfaces can and do act as the clock master. FireWire is a peer-to-peer interface, so there is no requirement that the PC be master of anything, clock or data. Also, you can be sure that I would not be talking about FireWire-to-I2S except that it is possible for the DAC to be master clock.
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