Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter - Page 237 - diyAudio
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Old 14th February 2013, 09:04 AM   #2361
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Quote:
Originally Posted by Blitz View Post
Wich Laptech did you choose and from where did you get it ?

Best Regards
Please, see the post #695
Ian asynchronous I2S and S/PDIF FIFO KIT group buy
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Old 14th February 2013, 09:16 AM   #2362
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Quote:
Originally Posted by soundcheck View Post
I do not intend to highjack this thread. Though it seems that some of the followers take my remarks about respectively reference to this project personal and attack me over here on presumably rather save ground.
I haven't taken anything personal or tried to attack you, I've just tried to help you with the areas that you said you had concerns about.

I had posted exactly my earlier post over on the other thread. I decided that if we were to talk specifics about the FIFO design, it was inappropriate in a Vendor's Bazaar thread about a different product, I won't cowardly trash a product in a separate thread, see how that sword cuts both ways?


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Originally Posted by soundcheck View Post
Please, don't put things out of context!!!
What exactly did I take out of context? Your post was specific in that you were concerned about Ian's use of the word ultimate and that you were not convinced that transport side tweaking would be no longer necessary with the FIFO+Reclocker. I tried to post specific information that was backed up by measured and as close to scientific as practical in DIY findings in this thread, most of which are by Ian's thorough work.


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Originally Posted by soundcheck View Post
That's why I won't accept a "should-not-matter". I've got a pile of "should-not-matters" in the workshop. On the paper a plain Sabre claims "should-not-matter". People over here and elsewhere (including me) experienced what that means.
Hardware is the root cause of the issue. People filtering a USB cable or a computer power cable or using a linear PSU for a computer or futzing about with software tweaks are not actually addressing the real system level issue. Whatever is being filtered should not have been in the signal wires in the first place IMO.

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Originally Posted by soundcheck View Post
Either somebody who's is running Ian's reclocker has tested thouroughly the reclocker against all kind of transport sided optimsations resp. variations or not. Measurements alone won't suffice.

If Ian managed to get all this under control, for sure he can make a fortune with his stuff. If upstream improvements would still make a difference, even with the reclocker in place, it would just be another card... ...and he might be challenged to get it done even better on the next revision.

Cheers
Unfortunately all 'experts' on software side optimisations are biased. They have typically invested time and money in minutiae of details that are just a way to avoid dealing with root cause issues that are in the hardware they have chosen.

As Andrea points out, if measurements aren't enough then try a few different crystals and find your favourite and enjoy. Funnily, this is also Ian's recommendation in the Dual XO manual from memory


Of the issues that I mentioned as caveats:

- The clock is the end user's choice. Choose one that suits your preferred jitter spectrum, measured jitter performance, subjective taste, whatever your flavour it is the single largest influence on sound output of Ian's FIFO. Once the jitter of the clock is below all sane measurement thresholds it is possible that the flip flops used for reclocking the signals are the dominant jitter source. At that point you're on your own.

- Conducted noise from the transport and FPGA are addressed with properly designed, PCB, decoupling and an additional isolator if you chose to build that PCB also. Power your transport with a heretic-like SMPS or USB power, no worries. But please be sure to power the XO with a regulator that suits HF oscillator loads, Ian even has discussed changes between Tantalum or X7R MLCC caps on the TPS7A4700 regulator that he has designed or type of mechanical isolation for the oscillator board that may have impact on the jitter spectrum; that is the level of minutiae he is working with.

It really is important to take the comments in this thread in context, the comments are quite often dealing with a level of detail not often discussed on DIY pages by people who actually know who they're talking about. Often armchair experts will mention some big words on forums to big note themselves, here Ian is basically giving his design time away for free. If you wanted to pay his hourly rate, then not many on these forums would be paying the asking price.

- Radiated noise - frankly if your DIY construction is susceptible to radiated noise then you should be taking a long hard look in the mirror, it is wiring and PCB choice and the way you mount it in the enclosure. All of these things can be addressed, by you, nothing that Ian or any designer does can address radiated noise.


I have not posted an absolute statement that the transport side will not make any impact because I (and anyone else) cannot guarantee that your construction methods are sufficient to ameliorate the above stated issues that are, in every DIY project ever, the responsibility of the DIYer. Also, I believe this statement from Obi Wan Kenobi in Revenge of the Sith is enlightenting:

Quote:
Only a Sith deals in absolutes.

If you can add to the list above I am all ears, though I'd want some pretty compelling presentation, based in reality not conjecture, as to what exactly might be going on.


Cheers,
Chris
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Old 14th February 2013, 12:56 PM   #2363
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I havn't seen any convincing argument that would make me go on with this.

All this talk won't get anybody any further.


And... ...if SW experts are biased (and narrow minded -- or nicer -- focussed) , then don't forget to put the HW expert fraction on the list.
That's a general problem of being an expert.

Enjoy. (Unsubscribed)
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Old 14th February 2013, 01:01 PM   #2364
Nikitas is offline Nikitas  Greece
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Default TPS regulator

I was wondering about the TPS regulator, how do you use it?
By connecting it directly to the rectifier? Are you using a filter? Or...?
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Old 14th February 2013, 01:09 PM   #2365
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Originally Posted by Odysseas View Post
I was wondering about the TPS regulator, how do you use it?
By connecting it directly to the rectifier? Are you using a filter? Or...?
The TPS reg needs rect, filtering and probably a pre-reg then it can act as a 3pin local regulator...

Ian has a section about that in the recently posted Si570 manual
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Old 14th February 2013, 01:32 PM   #2366
qusp is offline qusp  Australia
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Quote:
Originally Posted by soundcheck View Post
I havn't seen any convincing argument that would make me go on with this.

All this talk won't get anybody any further.


And... ...if SW experts are biased (and narrow minded -- or nicer -- focussed) , then don't forget to put the HW expert fraction on the list.
That's a general problem of being an expert.

Enjoy. (Unsubscribed)
as if you would ever endorse something that would render your long fought 'expertise' redundant anyway, pretty sure you only read the pages for the anecdotes.

if you are not convinced at this stage, then there is no saving you. part of the enjoyment must be having something to fret about and conspiracies to mumble under your breath

Last edited by qusp; 14th February 2013 at 01:35 PM.
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Old 14th February 2013, 02:00 PM   #2367
qusp is offline qusp  Australia
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part of having an open mind is recognizing a better and more complete solution when you see it, even if it means leaving things behind. if we take a leaf out of your book, all efforts are fruitless and the quarks hold all the cards. I can understand someone that may feel fifo to be an OTT solution, or simply something that doesnt fit their goals just yet (the need for an all in one AV or DSD solution), but as far as i'm concerned, the votes are in and it does what it was designed to do. properly implemented, the demons are vanquished.

for those who feel my comment above harsh, there are some theories in the other thread about hochopeper and I being one and the same... nope, we just both subscribe in general to similar branches of scientific endeavor based on knowledge accrued by others blazing the trails. Funnily enough, there are many things which are agreed upon and quite demonstrable/repeatable to those willing to keep an open mind.....

typical that you were hiding at the Brissie head-fi meet Chris, there is only photos of me posing with a ridiculous Eichmann power cord sash (not mine) ala Mike Tyson and photos of your Dac and your leg

Last edited by qusp; 14th February 2013 at 02:06 PM.
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Old 14th February 2013, 11:21 PM   #2368
Bunpei is offline Bunpei  Japan
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Quote:
Originally Posted by Bunpei View Post
Does the "Kphi: 0.249" mean "Phase Jitter = 0.249 [ps RMS]"?
I'm very sorry that I made a terrible mistake.
"Kphi" is a "Phase detector gain [V/rad]" of the measurement system.

By using the calculator shown in the glt's blog page, I calculated a phase jitter value from the phase noise plot and got 0.258 [ps RMS].
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Old 15th February 2013, 01:22 AM   #2369
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Default Si570 Clock Board R&D history review: Ver1.0, 2.0, 3.0, 3.5

It took me eight months to develop this small Si570 clock board. PCB has been re-designed and prototyped for four times, as well as the driver firmware. I didnít decide to publish it until I went through all V1.0, V2.0, V3.0, V3.5 versions.

I got a little bit pressure because so many people are waiting for it. Iím sorry for keeping you waiting too long. Please forgive me I just donít want to give up pursuing perfect, though I know Iím still far from it.

Iím an engineer and an audiophile. I trust science, measurement and my ears. I like this diyAudio community which has good ambiance to share the joy of project with each other. I just feel a bit unfair and donít understand why somebody upset I keeping improve on my project. Did I move anybodyís cheese?

Ian
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File Type: jpg Si570ClockBoardV3.0.JPG (356.2 KB, 271 views)
File Type: jpg Si570ClockBoardV3.5.JPG (685.0 KB, 274 views)
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Last edited by iancanada; 15th February 2013 at 01:28 AM.
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Old 15th February 2013, 02:14 AM   #2370
PET-240 is offline PET-240  Australia
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Don't stress Ian, some people just have their head up their bum complaining about the smell and not being able to find the light switch.
These things take time and is something most people COULDNT do, I can understand the concepts but the actual design etc........beyond my current skills and to be honest, interests.
I'm interested in making sure your time isn't wasted by people complaining because they can.
Most of what they speak should be flushed down the dunny, wonder where they get that from.......
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