Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter

[iancanada]

Originally Posted by merlin2069er

Very nice. Will it be available soon?

Happy New Year! Just back to work from holiday. Hopefully I could show you something very soon.

Ian

[iancanada]

I opened this Asynchronous I2S FIFO developing thread on Jul 12, 2011. Six months have passed. And now, it seems that the project is going very well. As an audiophile and a R&D engineer, I have to say, this concept is really working.

What I have achieved so for are:
1. I2S FIFO Board with attached Single XO Clock Board (PCB is the third edition).
2. Dual XO Clock Board (PCB is the third edition).
3. S/PDIF Interface Board (PCB is the third edition).

Quite a few friends are very interested in this project, and some of them encouraged me setting up a group buy. I like that idea. Because, for me, it would my great pleasure if I could share the output of this project with other audiophiles by setting up a group buy. But to do so, there would be a great deal of jobs. Just let me figure it out.

Once I’m ready, I will open a new GB thread on the Commercial Sector / Group Buy area of DiyAudio Forums, while keep this thread for technical discusses only.

I attached the pictures of the three up to date PCB assembling boards and corresponding PDF user’s manuals below for reference.

Ian

[Algar_emi]

Count me in for the GB. Wow great documentation already.
Thanks...

[SunShade]

Hi Ian,
great project. A couple of questions.
What is the reason you choose to use three PCBs instead of one?
Even if someone doesn't need the SPDIF input, e.g. they want to use USB, the savings on PCB, interconnects etc. are probably in the range of the cost of the SPDIF section anyhow?

In your experience, what is the best performance in terms of jitter that can be achieved using an integrated (single chip or DSP e.g. ADI) ASRC vs your very nice design?

[zinsula]

Hello Ian, can you enlighten me about the regulator for the clock. Does it have to be supplied externally?
Thank you

[iancanada]

Originally Posted by zinsula

Hello Ian, can you enlighten me about the regulator for the clock. Does it have to be supplied externally?

zinsula,

Any 5V-6V regulated DC power supply is OK for the FIFO KIT, beacuse filters and low noise LDOs already equiped on board. However, if you have really nice low jitter clock, low noise high performance DC power supply is prefered for the last drop of juice. For eaxmple, the GB Salas low voltage shunt reg would be one of the good choices. Batteries could be good reference to help you making the right decision.

Usually you don't need external power supply for the clock board, because on board LDOs and filters for the clocks are independent from other sections.

Ian

[zinsula]

Ian,
do I understand correctly:
- the clock board does have already the regulators on board
- there is no easy and meningful possibility to bypass them? (of course there is not much sense in placing the reg, as good as it might be, iches away from the clock)

I'm asking as low noise is of utmost importance for a good clock to perform at it's best,
and since I believe that no LDO will match a regulator eg. Demian has presented here.

Btw, did you already test the Tent clock?

[qusp]

at these frequencies the decoupling caps will still do most of the heavy lifting in any regulator scenario anyway, so transient response is imo pretty meaningless, while low noise is still pretty meaningful, does demians regulator produce better than 9uV RMS? it may well do as the man knows what hes doing (yes i saved the schematic back then too), but yes you guessed it, the physical placement offboard is likely to render it fairly incidental

any upgrade i might play with might be batteries

[zinsula]

Low 1/f corner frequency IS important.

[iancanada]

Hi zinsula,

Yes, the clock board already equiped with low noise regulators on board.
However optional external power input port has been left for skilled diyers,bypassing the onboard LDO is very easy as well, just disconnect some FBs. If you like, I could even supply clock board without LDO.
Talking about clocks, yes, I tested quite a few of them, include the Tent clock.

Ian