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Old 30th March 2011, 12:30 PM   #221
jkeny is offline jkeny  Ireland
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At the risk of being told that I shouldn't be posting here, my experience (& others) is that these GMR isolators do have a negative sonic impact & it's best to leave them out. I don't find any noticeable noise issues from the laptop/PC/Mac that warrants isolators.
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Old 30th March 2011, 02:15 PM   #222
exa065 is offline exa065  Canada
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GMR's are easy to bypass, however I wouldn't recommend it. There is a certain integrity in the design and taking away any piece will deteriorate the overall quality and stability of the exaU2I device. In some of our test environments the impact of noise due to ground loops, especially when a TV is involved in the setup was huge compared to the undetectable increase of jitter. The overall sonic performance will be limited by the weakest, worst performing link in the data processing chain. It is unlikely that the GMR's are on the priority list.

From our perspective, not having to worry about ground loops and common noise is one of the main advantages of exaU2I that can increase the likelihood of success for a DIY project.
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Last edited by exa065; 30th March 2011 at 02:26 PM.
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Old 30th March 2011, 03:06 PM   #223
jkeny is offline jkeny  Ireland
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Sorry, EXA, I'm not being critical or putting down your product - I think it's great to see all these offerings for USB audio. In the context that you state TV use, I have no experience & you are probably correct - I was just trying to relate my experiences in audio.

I can't prove it (I don't have the equipment) but I'm pretty sure that jitter (I know it's meaningless to state a single figure without a spectrum analysis but I'm going to do so anyway) way below 100pS is audible a good audio set-up.

I'll not butt in on your thread any more.
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Old 30th March 2011, 03:07 PM   #224
Bunpei is offline Bunpei  Japan
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Quote:
Originally Posted by exa065 View Post
I am very pleased to announce that exaU2I is now officially the first asynchronous USB to I2S interface capable of streaming multichannel 32bit / 384 kHz data.
Congratulation! I think your achievement is truly plausible. As far as I know, the only other USB audio interface which covers 32bit / 384 kHz is USB 2 input option of MSB Diamond DAC IV.
USB 2 Input Option
However, I think it is neither asynchronous nor I2S output. Moreover, it's just a proprietary option for their DAC.

I convince the value of high sampling audio of fs >= 352.8 kHz. I hope your exaU2I products will boost the number of DIY users those who can enjoy those audio and that will encourage the rapid increase of attractive sources available in this market. This will also make SDTrans users happy.
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Old 30th March 2011, 05:57 PM   #225
exa065 is offline exa065  Canada
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Thanks! I am very grateful for the good words. After all this thread has been a great forum for free speech and critical evaluation. We have established what is achieved so far and what can make the exaU2I a better product.

I am considering creating an alternative device for use with non-reclocking DACs. Deploying a jitter canceling stage after the GMRs and allowing the use of external master clock will benefit the most demanding users. When I am redy to start this discussion I will create a new thread. Hopefully by that time I will be able to establish a Forum in the Manufactures' area.

I am really eager to see feedback from people that are using exaU2I in simple environments. Connecting a Buffalo DAC or an AckoDAC should be simple and straight-forward. Enabling a multi-channel setup will be a very exciting experience.
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Old 31st March 2011, 01:57 PM   #226
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Quote:
Originally Posted by jkeny View Post
At the risk of being told that I shouldn't be posting here, my experience (& others) is that these GMR isolators do have a negative sonic impact & it's best to leave them out. I don't find any noticeable noise issues from the laptop/PC/Mac that warrants isolators.
At least on SPDIF I can't run without pulsetransformer.
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Old 31st March 2011, 02:07 PM   #227
exa065 is offline exa065  Canada
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At least on SPDIF I can't run without pulsetransformer.
And without a clock line. SP/DIF clock is derived from the data and it is causes huge jitter compared to the jitter caused by the GMRs. You also have bandwidth limitations. Optical SP/DIF is even more constrained and more jittery than co-axial SP/DIF.
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Old 31st March 2011, 02:30 PM   #228
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Originally Posted by exa065 View Post
And without a clock line. SP/DIF clock is derived from the data and it is causes huge jitter compared to the jitter caused by the GMRs. You also have bandwidth limitations. Optical SP/DIF is even more constrained and more jittery than co-axial SP/DIF.
The question really is , what's done with SPDIF signal before converted to I2S.

You can't compare I2S and SPDIF that easily.
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Old 31st March 2011, 03:25 PM   #229
exa065 is offline exa065  Canada
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The question really is , what's done with SPDIF signal before converted to I2S.

You can't compare I2S and SPDIF that easily.
You shouldn't convert SPDIF to I2S. Why degrade the signal and then try to recover the lost information? SPDIF is an antiquated consumer interface. I2S is an opportunity to bypass the bandwidth bottle neck and the clocking limitation. Jitter from SPDIF is one of the major contributors to the "digital sound" of CD players.

It is quite easy to compare the two interfaces. The difference is like night and day.
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Old 31st March 2011, 03:50 PM   #230
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Originally Posted by exa065 View Post
You shouldn't convert SPDIF to I2S. Why degrade the signal and then try to recover the lost information? SPDIF is an antiquated consumer interface. I2S is an opportunity to bypass the bandwidth bottle neck and the clocking limitation. Jitter from SPDIF is one of the major contributors to the "digital sound" of CD players.

It is quite easy to compare the two interfaces. The difference is like night and day.
To my understanding you feed DACs I2S and not SPDIF. You gotta convert SPDIF at one point.

You can IMO achieve highest qualities with SPDIF if properly implemented.
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