XMOS-based Asynchronous USB to I2S interface

PSUs, mostly yes, though I consider this board still have a very good power supply network given the fact that XMOS chip is a "little" power hungry :)
DC-DC will be next thing, to keep power consumption down and minimize heat dissipation, but only after I'll find a way to isolate the I2S outputs from USB (whatever that means). I'm still thinking on how to do it... properly... without GMRs or other jittery devices.
On the other hand i want the best PSu for oscillators and it's hard to decide which PSu will fit all requirements! I was thinking to add W.Jung-like vregs for each oscillator in part. Shunts are also good enough (maybe better?)... I just don't know for now which one will be...
Regards,
L
 
Yeah...

that is why I only would suggest shunt(s) if an external supply (not USB bus) was mandated. Running a shunt for only the clocks alone could result in a nice improvement (and the clock reg should not require too much current) as the low output impedance of the shunt should keep the rest of the power supplies from getting modulated by the clock frequency. Perhaps adding just a single shunt for the clocks, and keeping linear regs for the the other supplies...
Just thinking out loud here.
 
I agree with barrows! Now, on this board there are three LP5900 Vreg chips: one for each oscillator in part and the third one is for I2S output logic.... and this only just to keep noise down as much as I can! Given this, it's hard for me to believe that I'll choose one shunt reg to power all clocks (excluding surrounding I2S logic).
So, if performance needs a little more power then I'll choose the external PSU path leaving the USB 5V supply for another time.
I'm still in with 1 x Walter Jung - like PSU followed by two shunt regs (one for each oscillator in part). Barrows?
 
Excellent optios

Hi:

I have been looking for such a board and want to praise your layout and options. The header out option for I2S is excellent, this way one can quickly try different cables and connection to different DACs. I liked the way you have given terminal input for external power supply. However, the best is the option to have two USB connections especially one with the header out so one can run cable to chassis thus mounting board really close to target I2s input for minimum I2S cables length.

Regards
 
Hi:

I have been looking for such a board and want to praise your layout and options. The header out option for I2S is excellent, this way one can quickly try different cables and connection to different DACs. I liked the way you have given terminal input for external power supply. However, the best is the option to have two USB connections especially one with the header out so one can run cable to chassis thus mounting board really close to target I2s input for minimum I2S cables length.

Regards
Thank you!

How does the measurements compare to the XMOS reference design? I means at SPDIF out and I2S out? Any graph comparison is good especially on Jitter and noise figures. If possible, please show how the test is conducted and equipment used.

Thank you
When I'll have the required informations I'll post them asap. For now, there are two members of this forum which could do noise and jitter tests and I'm still waiting an answer.

Very Nice board! Please let me know when you have these available for sale!
I still have few boards for sale... but my free time is absent thus I didn't had the chance to build up my site to reflect that. :snail:

Kind regards,
L
 
Hi All:

Just sharing my experience of purchasing and using the board from Lorien.

It works wonderfully. Everything is good and working. It turned out to be the way I expected, excellent. I used the interface board both with external power and USB power. I used the isolated I2S outputs to Philips TDA1541A DAC chip by providing the GMR with 5V. It has different but positive sound. It is little laid back, taken the bite off my tweeters, wider soundstage and much natural/organic sound than M2Tech HiFace (USB to S/PDIF) which is infamous for forward sound.

Again, excellent dream options to evaluate things that I don't see on any other board. Quality and inexpensive solution.
 
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Also using Lucian's board connected to BuffaloII/LegatoIII via SPDIF and bus power at the moment and it sounds great. Better than HiFace and eqaulling Musical Fidelity V-link. Will try I2S and external power(TP Placid shunt) soon and I'm sure it will improve the sound even more.

Lucian, thank you for your brilliant service:).
 
@ merlin el mago & @ regal: you have PM.

Thank you guys for all kind words about this card.. and mostly, for having patience with me... For now I want to catch up with a small revision to this card but time is still an issue for me thus I don't have a specific date. There are not big changes just I'm thinking to get rid of NVE isolators and make room to other type of connectors, like 2.54 mm headers for I2S signals since some of you encounter issues with those micro BNC connectors. We will see...
kind regards,
L
 
Yes, I am thinking to let USB-bus powering aside and opt for external source though this means to make some major changes on that card to fully isolate it from USB. For now my goal is preserve this price while bring few enhancements to the nonisolated I2S outputs like realigning the signals with onboard master clocks... because I'm not fully confident in XMOS's chip :eek:... even if XS1-L1 IC makes this happen already. On the other hand, few improvements in PSU is allways a benefit.
Regards,
L
 
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pity about losing the smd micro bnc, this is important for ackodac users. could you perhaps put pinheaders in parallel? i have had zero trouble with them and use them wherever possible, i have used them for power sense/feedback lines for low noise regulators with good results also. what did people have trouble with? soldering them?