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

[mcluxun]

From my reading on the i2s backdoor earlier in this thread it would appear that it is only required if you're using the spdif interface board to provide 'conventional' inputs; I only plan to have a network feed via the rpi so I think I just need to route the rpi i2s output straight to the FIFO board?

Thanks

Ray

Yes if you are building a player in one box (rpi+fifo+dac) you can use the fifo board alone.
you dont need the mclk input for fifo either.

 

[hochopeper]

There was also something about using a fuse inline when testing to safeguard the boards...from qusp I think.

That's a good suggestion, but was mostly aimed at one builder who had a penchant for making things burn rather than doing thorough testing before applying power. Especially note that batteries are capable of higher short circuit current output than many linear power supplies so when powering a newly assembled board for first time .... batteries are a poor choice.

 

[mcluxun]

I remembered there was someone in this thread talking about the length of cable and mclk delay.
Here is a real world question:
I'd like to run buffalo III in synchronized mode.
Due to the layout I can choose:
1 3×10cm ufl cable for data and 20cm for clock
2 4×20cm cable for all of them.
Which will work better?

 

[palmito]

I remembered there was someone in this thread talking about the length of cable and mclk delay

I think it was qusp?

 

[mcluxun]

I think it was qusp?

yeah I found that thread qusp said they should be the same length.
ufl cables are so expensive....

 

[Crom]

Definitely all the same length but I couldn't get a decent lock with 20cm on my dual mono set up. I ended up with these which work perfectly:

U.FL-2LP-088K1T-A-(100) - HRS (HIROSE) - CABLE, PLUG/PLUG, 1.37MM, 100MM | Farnell UK

Yes, not cheap and v fiddly. The longer you get try to increase the diameter of the cable too - I'm trying to find a supplier of 1.78mm cables as Ian recommended them in his FIFO thread.

Hope this helps.

 

[mcluxun]

Definitely all the same length but I couldn't get a decent lock with 20cm on my dual mono set up. I ended up with these which work perfectly:

U.FL-2LP-088K1T-A-(100) - HRS (HIROSE) - CABLE, PLUG/PLUG, 1.37MM, 100MM | Farnell UK

Yes, not cheap and v fiddly. The longer you get try to increase the diameter of the cable too - I'm trying to find a supplier of 1.78mm cables as Ian recommended them in his FIFO thread.

Hope this helps.

If I tweak my layout a little bit, I can probably try 4*15cm cables.
But what I have right now are either 10cm or 20cm.
The best I can find is 1.32mm from mouser.
The 1.78mm one should be following RG178 standard, which I didnt find any u.fl to u.fl.

 

[Crom]

Yes, I normally use Mouser but they didn't have what I wanted so I had to go to Farnell...have you tried digikey? Might be worth asking Ian where he sourced the 1.78mm

...Ian?

 

[clsidxxl]

I found here SMA, 3G UMST EV-DO antenna items in connector store on eBay! , custom cable on request,I waiting for a command from a UFL to UFL RG 178 of 8cm for the MCLK,cost with transport 3,50 Dollard.By against the delivery time is long 25 at 30 days.

 

[clsidxxl]

I remembered there was someone in this thread talking about the length of cable and mclk delay.
Here is a real world question:
I'd like to run buffalo III in synchronized mode.
Due to the layout I can choose:
1 3×10cm ufl cable for data and 20cm for clock
2 4×20cm cable for all of them.
Which will work better?

To run DAC in dual mono mode, I’m highly recommended using u.fl coaxial cables with same length to guarantee signals arrive at each block at same moment. Please keep in mind, every 1 inch 50ohm coaxial cable will cause roughly 120ps delay on signal!

That’s one of the black magic of a digital cable: vibration and jitter

Ian

 

[mcluxun]

So is that same length thing for dual mono only or for all, Im confused.

 

[clsidxxl]

you think too muchsame length for all signals to single output and dual mono,dual mono is specified by Ian because more sensitive to different length.

 

[Nikitas]

Any ideas about where can I get some of the ufl cables?

 

[deanoUK]

Any ideas about where can I get some of the ufl cables?

Farnell Nederland | elektronische componenten | Elektronische onderdelen

 

[Nikitas]

yeah but those aren't the same thing exactly..

 

[deanoUK]

The same as what ?

 

[Nikitas]

the cables that Ian sent with his kit.

 

[deanoUK]

I have used the HRS (HIROSE) ones with no problems.

 

[iancanada]

To run DAC in dual mono mode, I’m highly recommended using u.fl coaxial cables with same length to guarantee signals arrive at each block at same moment. Please keep in mind, every 1 inch 50ohm coaxial cable will cause roughly 120ps delay on signal!

That’s one of the black magic of a digital cable: vibration and jitter

Ian

So is that same length thing for dual mono only or for all, Im confused.

What I mean same length of u.fl coaxial cable was just for MCLK cables. For other signals, you don't have to use cables with same length, but it would be better longer than the MCLK cable.

Ian

 

[iancanada]

Yes, I normally use Mouser but they didn't have what I wanted so I had to go to Farnell...have you tried digikey? Might be worth asking Ian where he sourced the 1.78mm

...Ian?

I ordered 178 u.fl cables from our cable supplier, but the minimal order has to be 500 . I couldn't find any 178 cable with u.fl connector from Digikey or Mouse at that time.

178 has less loss. Is there anybody get it compared with normal u.fl cable?

Ian