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

[andrea_mori]

Originally Posted by iancanada

Hi Andrea,
I'll upgrade the FIFO KIT supporting the left justified format before the second run.
I'm not familiar with XO3. If it is a good clock, you may feed it into the clock board of the FIFO KIT. Any re-clock before FIFO is useless. Because clock was isolated.

Hi Ian,

thanks for upgrade. Do you implement this feature in a new bord?

About PLL reclocking I meant after FIFO, before DAC or DF.

[vzs]

Hi Ian,
Regarding Andrea's CDPro - FIFO issue: if I understand well CDPro uses SAA7372 or SAA7374, both output I2S in 48bit format not 64, thus the output SCK according to the manual is 2.1168MHz
Can the FIFO handle this? - if not he can still use the spdif output of CDPro with your spdif board then the FIFO but not direct I2S
Thanks,
Zsolt

[wktk_smile]

Hi, Ian

Your FIFO+reclocker combined with Sabre dac is really impressive, especially when synchronous mode between the dac and reclocker.

When I first fired up SDTrans384 - FIFO plus reclocker( U1 is replaced with NDK NZ2520SD ) - Buffalo2 setup, I immediately noticed this obviously outperforms SDTrans384 - Buffalo2 combo.
Side by side comparison was never needed.

Now I can hear more low-level informations more easily and feel as if near the everything some more precise - bass are better controlled, less harsh Hi, and so on.

Really good job indeed, and I'm glad to see you still seek more improvement and versatility...


Thanks!

[wktk_smile]

DSD support and capability of faster MCLK output would be nice if the board revisions were
planned in the future

[andrea_mori]

Originally Posted by vzs

If you did not removed the original crystal oscillator from your CD Pro this XO3 module is indeed useless.
I hoped you can use the XO clock from it, but not with this frequency.

I'm wondering what is the bit clock of the I2S at the CD PRO out

I think 33.8688 Mhz.
It use SAA7324
(http://www.daisy-laser.com/products/.../SAA7324_2.pdf).

[vzs]

Originally Posted by andrea_mori

I think 33.8688 Mhz.
It use SAA7324
(http://www.daisy-laser.com/products/.../SAA7324_2.pdf).

Same as for the others - see page 18: for 1xfs the SCLK = 2.1168MHz or multiples of this so 48bit I2S frame.
Let's wait to see what Ian says about this. In worst case you use the spdif out of CDPro to spdif board of FIFO.

[soundcheck]

Hi guys.

Interesting project.

Let me ask you a question.

Pretty much all computer audio interfaces suffer of noise, jitter, intermodulations, drifts, you name it, fed from the PC or transport via USB, SPDIF, you name it.

Slightest optimizations (HW/SW) on the transport side usually have an impact on the sound. (See my Touch Toolbox effects, audiophile SW player effects, .wav vs. .flac., asf. asf.

I'm not aware of any audiointerface which wouldn't respond to those upstream optimizations.

Now. If for example I'd connect a Wave-IO XMOS USB interface (you might have followed discussions over here at DIY-audio) and the reclocker,
do you guys think, the impact of the upstream mess would be gone -- as long words and bits are the same????

Thx for your feedback.

Cheers

[iancanada]

Originally Posted by vzs

Hi Ian,
Regarding Andrea's CDPro - FIFO issue: if I understand well CDPro uses SAA7372 or SAA7374, both output I2S in 48bit format not 64, thus the output SCK according to the manual is 2.1168MHz
Can the FIFO handle this? - if not he can still use the spdif output of CDPro with your spdif board then the FIFO but not direct I2S
Thanks,
Zsolt

Hi Vzs,

My FIFO is 100% compatible with I2S standard. So, it doesn't matter how many sck per word or sck frequency. Any word length between true 16bit to true 32bit is working. Thank you so much for noticing me about that.

For Andrea's project, if that XO3 is just for upgrading CDPro, then with the FIFO attached, I don't think he need it. He just need connect the I2S output directly from the CDPro into the FIFO.

[andrea_mori]

Originally Posted by vzs

Same as for the others - see page 18: for 1xfs the SCLK = 2.1168MHz or multiples of this so 48bit I2S frame.
Let's wait to see what Ian says about this. In worst case you use the spdif out of CDPro to spdif board of FIFO.

I've seen the datasheet, 2.1168 x n.
Spdif in not the best solution, I2S is definitely a cleaner solution, but if no other solution I'll use spdif.

Well, I'm waiting for Ian impression about this.

[andrea_mori]

Originally Posted by iancanada

Hi Vzs,

My FIFO is 100% compatible with I2S standard. So, it doesn't matter how many sck per word or sck frequency. Any word length between true 16bit to true 32bit is working. Thank you so much for noticing me about that.

For Andrea's project, if that XO3 is just for upgrading CDPro, then with the FIFO attached, I don't think he need it. He just need connect the I2S output directly from the CDPro into the FIFO.

Ian

Good news for me!
at this point is missing only to feed directly NPC, so my project will be complete.

Thanks