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Old 2nd May 2011, 05:10 PM   #441
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Quote:
Originally Posted by RayCtech View Post
It appeare that a whole section was removed by accident when I edited the post...

A calculated improvement in jitter of up to 60 dB...
It may not be measurable by more than a few dBs..
But I expect it would affect the fidelity...
This was not completely accurate...

60dB is a calculated maximum possible improvement on the bit clock as a theoretical worst case scenario.
A 1ps jitter clock vs a 2ns variation of the GMRs,
but as an example with a ES9018 chip this would have little or barely no effect at all as only the jitter on the word clock would matter as long as the correct "0" and "1" data bits are clocked in..
What matters on a ES9018 are the word clock.
Jitter on the word clock will be mostly removed by the ES9018 jitter removal circuit.

Also on a PCM1704 the bit clock are only used to shift the data into a serial buffer and it is the word clock that would be sensitive for jitter.
The word clock latches the data from the serial buffer into a parallel buffer for further processing.

The word clock will only be affected of 1/64 times of the jitter a GMR isolator might introduce compared to the bit clock.
With a PCM1704 without any jitter removal circuit this may make a difference compared to a ES9018 where any jitter will be greatly reduced.

Last edited by RayCtech; 2nd May 2011 at 05:12 PM.
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Old 2nd May 2011, 07:09 PM   #442
jkeny is offline jkeny  Ireland
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Quote:
Originally Posted by RayCtech View Post
.......
Jitter on the word clock will be mostly removed by the ES9018 jitter removal circuit.
.......
Do you have empirical evidence of this or are you just believing the ESS marketing department? Have you heard any difference between GMR isolator in circuit & out of circuit?
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Old 2nd May 2011, 07:12 PM   #443
exa065 is offline exa065  Canada
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Quote:
Originally Posted by kazap View Post
I wonder if I can get some opinions about a nutty idea I just had.

Is there any merit in feeding my stereo DAC that has eight DA chips with eight I2S streams via the exaU2I?

I have the Audio-gd REF7 ͧ*响. I really like the sound signature of this eight piece PCM1704 R2R mono chip but it does seem to be very sensitive to jitter.

The REF7 is fed by SPDIF and has a jitter reducing DSP module (http://www.audio-gd.com/Pro/dac/DSP1/DSP1ENspecs.htm Two-channel Digital Interpolation Filter and data in-phase processor for digital audio),that takes I2S, upsamples if you like and splits I2S into left and right channels for the mono PCM1704's (four on each side).

I guess Foobar can use VST (Virtual Studio Technology) and DSP's to create four left only channels and four right only channels.

If these were taken out of the exaU2I by identical wires to feed each chip discreetly would it work?

If it makes music I wonder if you might care to speculate which will sound better.
A)a single I2S stereo signal to the DSP-1
B) Eight discreet I2S mono signals - one per PCM1704

Cheers
Hello Kazap,
I will speculate that it will sound better without the DSP-1. You will know for sure after you try it both ways and ask your wife for a blind test .
It is easy to assign 4 left and 4 right channels with the exaU2I ASIO driver. Later today I will read about PCM1704 to see if a little firmware modification is required to have a clean solution and to make your life simpler.

Cheers,

eha065
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Old 2nd May 2011, 07:15 PM   #444
exa065 is offline exa065  Canada
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Quote:
Originally Posted by jkeny View Post
Do you have empirical evidence of this or are you just believing the ESS marketing department? Have you heard any difference between GMR isolator in circuit & out of circuit?
Here we go again .
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Old 2nd May 2011, 07:26 PM   #445
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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.
Quote:
Originally Posted by jkeny View Post
Do you have empirical evidence of this or are you just believing the ESS marketing department? Have you heard any difference between GMR isolator in circuit & out of circuit?
I was trusting in your statement in the first "quote" was empirical evidence

Maybe the "negative sonic impact" you states are caused by something else than "jitter" when YOU experience the phenomenon

Even if you states
Quote:
I don't find any noticeable noise issues from the laptop/PC/Mac that warrants isolators
I would recommend that you evaluates what USB galvanic isolation will do first....

Last edited by RayCtech; 2nd May 2011 at 07:32 PM.
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Old 2nd May 2011, 07:31 PM   #446
jkeny is offline jkeny  Ireland
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Originally Posted by exa065 View Post
Here we go again .
Sorry, yes I forgot I posted about this already - I'm outta here!

Maybe others will give their opinion based on bypassing the isolators?

Last edited by jkeny; 2nd May 2011 at 07:34 PM.
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Old 2nd May 2011, 07:40 PM   #447
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Originally Posted by jkeny View Post
Sorry, yes I forgot I posted about this already - I'm outta here!
It appear a bit strange when you switches your arguments when you have forgotten what you argument was against / for the last time you posted ??

Last edited by RayCtech; 2nd May 2011 at 07:42 PM.
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Old 2nd May 2011, 07:50 PM   #448
jkeny is offline jkeny  Ireland
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Sorry EXA but RayCtech has to be answered!

What? I'm not switching arguments? Maybe you don't understand?

As I sated before - GMR isolators in the I2S lines degrade the sound, probably as a result of their added jitter & the jitter reduction of the Sabre DAC will not negate this (no matter what ESS marketing says). No different from what I said before except for the ESS bit added in.
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Old 2nd May 2011, 08:29 PM   #449
exa065 is offline exa065  Canada
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Quote:
Originally Posted by jkeny View Post
Sorry EXA but RayCtech has to be answered!

What? I'm not switching arguments? Maybe you don't understand?

As I sated before - GMR isolators in the I2S lines degrade the sound, probably as a result of their added jitter & the jitter reduction of the Sabre DAC will not negate this (no matter what ESS marketing says). No different from what I said before except for the ESS bit added in.
Hi John,

I don't want you to abandon the thread. I just need to avoid opening again topics where we agreed to disagree. There are plenty of devices without GMRs. People can also remove the GMR's from the exaU2I and decide for themselves if there is more gain or more loss.

Regarding the ESS advertising, I am amazed how silly are the attacks against the capabilities of their jitter removal technology. I speak here as a DIY person. ES 9018 is one of the best things that happen to my personal system for the past 20 years. Perhaps people have disappointments with their product because they don't have the specifications and the knowledge to use it properly.

The real exaU2I jitter is less than the calculated about 100ps. And there is more to exaU2I than jitter. It is a fine package that delivers clean, dynamic and detailed sound. We haven't had a single user saying that the for the improvement it brings the board is too expensive. I fact all of our users are enthusiastic about exaU2I.

Regards,

exa065
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Old 2nd May 2011, 08:40 PM   #450
jkeny is offline jkeny  Ireland
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Quote:
Originally Posted by exa065 View Post
Hi John,

I don't want you to abandon the thread. I just need to avoid opening again topics where we agreed to disagree. There are plenty of devices without GMRs. People can also remove the GMR's from the exaU2I and decide for themselves if there is more gain or more loss.
Sure, & maybe some users of the EXA will try bypassing the GMR device & reporting their sonic findings?

Quote:
Regarding the ESS advertising, I am amazed how silly are the attacks against the capabilities of their jitter removal technology. I speak here as a DIY person. ES 9018 is one of the best things that happen to my personal system for the past 20 years. Perhaps people have disappointments with their product because they don't have the specifications and the knowledge to use it properly.
Maybe you missed this post Anybody using the new ESS Vout DAC (ES9022)?
And the extract by some ex-design engineers of the ESS
Quote:
"The clock (timing source) is critical. Although the Sabre DAC has on-chip re-synchronization to its master clock, higher performance can be achieved by controlling the relative phase of the system and the DAC clocks."
Quote:
The real exaU2I jitter is less than the calculated about 100ps. And there is more to exaU2I than jitter. It is a fine package that delivers clean, dynamic and detailed sound. We haven't had a single user saying that the for the improvement it brings the board is too expensive. I fact all of our users are enthusiastic about exaU2I.

Regards,

exa065
Sure, Exa, I don't doubt about what you say.

Last edited by jkeny; 2nd May 2011 at 08:45 PM.
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