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

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#3,731
aive said:
Hey Ian, I got the goods! Thanks again.

This is going to seem like a really dumb question - but which positions do I place the resistors and capacitors on the SMT XO adaptor PCBs >< I can't tell where they go ><

Thanks Ian.
Click to expand...

Oops I mean, where do the supplied capacitors go on the SMT XO adaptor PCBs? (there aren't any resistors sorry, my mistake)

And are they required if I use CCHD-957 clocks? 🙂

Edit: nvm, I found you had already answered these questions 🙂

XO Adaptor Manual:
http://www.diyaudio.com/forums/grou...-s-pdif-fifo-kit-group-buy-8.html#post3093337

And re CCHD-957 decoupling caps:
iancanada said:
Yes, it does. You don't need the MLCC for CCHD-957.

Regards,

Ian
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Last edited:
#3,732
aive said:
Oops I mean, where do the supplied capacitors go on the SMT XO adaptor PCBs? (there aren't any resistors sorry, my mistake)

And are they required if I use CCHD-957 clocks? 🙂

Thanks Ian.
Click to expand...

Hi aive,

Sorry for the confusing.

At back of the XO adapter PCB, two 0603 0.1u(104) MLCCs go to the smaller footprints, one 0805 1u(105) MLCC goes to the bigger footprint.

You need those capacitors for any XO to reduce power supply ripple caused by the inductor of the lead.

Regards
Ian
 
#3,733
iancanada said:
Hi aive,

Sorry for the confusing.

At back of the XO adapter PCB, two 0603 0.1u(104) MLCCs go to the smaller footprints, one 0805 1u(105) MLCC goes to the bigger footprint.

You need those capacitors for any XO to reduce power supply ripple caused by the inductor of the lead.

Regards
Ian
Click to expand...

Hey Ian, thanks for reply! I must have very bad eyes, cus the footprints all look the same size to me >< But I found your instructions in previous GBII 😀 so I will install capacitors as per photos.
 
#3,735
iancanada said:
At back of the XO adapter PCB, two 0603 0.1u(104) MLCCs go to the smaller footprints, one 0805 1u(105) MLCC goes to the bigger footprint.

You need those capacitors for any XO to reduce power supply ripple caused by the inductor of the lead.

Regards
Ian
Click to expand...

Hi Ian,

Ah, now I'm confused.

Are these caps still a good idea with use of Dual XO when supplied by external DC to J5 and with FB L11 removed ?

(ref: DualXOclockboard.pdf page 4)

It works fine without the caps CCHD-957's (to my ears) but now I wonder if further improvement could be had.


Thanks.

L.H/S
 
#3,736
Ludwig Haus said:
Hi Ian,

Ah, now I'm confused.

Are these caps still a good idea with use of Dual XO when supplied by external DC to J5 and with FB L11 removed ?

(ref: DualXOclockboard.pdf page 4)

It works fine without the caps CCHD-957's (to my ears) but now I wonder if further improvement could be had.


Thanks.

L.H/S
Click to expand...

Hi L.H/S

Technically it will be a bit better for reducing noise with those capacitors. Some noise is caused by the inductance of the lead and PCB trace of XO itself(not from power supply) , those capacitors were designed exactly for that case.

Of course it will work fine without them. So, the finial decision will be made up to your preference based on your real listening experience 🙂.

Regards,
Ian
 
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