diyAudio

diyAudio (https://www.diyaudio.com/forums/index.php)
-   Digital Line Level (https://www.diyaudio.com/forums/digital-line-level/)
-   -   XMOS-based Asynchronous USB to I2S interface (https://www.diyaudio.com/forums/digital-line-level/188902-xmos-based-asynchronous-usb-i2s-interface.html)

Lorien 10th August 2011 08:40 AM

Perhaps cable adaptors are a little bit expensive compared to simple wires and 2.54 mm headers. And yes, it could be difficult for some people to solder these conns. Though, I am convinced, like you, that uBNC (or U.FL. in my case) should be taken into account thus I'll see if there's room for pinheaders besides uBNC.

Thank you qusp for feedback!
L

qusp 10th August 2011 09:31 AM

what you could do and i would certainly throw in for some of these for other projects, would be to throw a simple 4 or 7 (multiple grounds) pin 2.54 pinheader to 3-4 x bnc (with or without mclk) adapter pcb, plus perhaps a simple 1 or 2 ubnc to 1-2 fullsize board mount RCA/BNC for coax for output and input connections onto spare space on an existing job. shouldnt cost more than a few dollars each, or depending on your board manufacturer possibly almost free if spare space is utilized.

w.fl connectors can actually be soldered onto the u.fl land pattern and vice versa pretty easily, or as they are so tiny you could have both patterns in parallel, or a custom pattern could be made somewhere in between to fit both for those who have difficulty. probably both in parallel would be best.

DVBjunky 10th August 2011 09:31 AM

Hi,

I am also very interested in your Design and want it to include in my Class D project.
As soon you are finished and have any prices available - let us know.

cheers

Alan

vanwykca 10th August 2011 11:02 AM

I've now tried the U.FL I2S into BuffII/LegatoIII and it's without doubt better than the SPDIF. Also, I have no problem with lock using lowest DPLL bandwidth and 24/192 files. When I tried I2S/DSD from Denon 2900 using CAT6 cable, I had issues with intermittent dropout that was only solved using Acko MCU AKC12 to open up the DPLL bandwidth (this is on my 2nd Dac, BUFFII/IVYIII).

It seems Lucian's device has quite low jitter via I2S, as a lot of other users of the BuffII struggled with I2S lock and lowest DPLL bandwidth.

http://www.flickr.com/photos/56308196@N04/6028891956/http://www.flickr.com/photos/56308196@N04/6028337551/

merlin el mago 10th August 2011 11:13 AM

Lucian your USB-I2S interface have a switch for USB-S/PDIF?

regal 10th August 2011 12:23 PM

Quote:

Originally Posted by Lorien (https://www.diyaudio.com/forums/digital-line-level/188902-xmos-based-asynchronous-usb-i2s-interface-post2666856.html#post2666856)
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 :o... even if XS1-L1 IC makes this happen already. On the other hand, few improvements in PSU is allways a benefit.
Regards,
L

Very smart move to reclock after the xmos. As far as the galvanic isolation have you considered a manual switch to select a lower USB rate (12 Mbit/s) that would allow galvanic isolation with adum's on the USB side ( but possibly loosing hirez,) It would be a real boon for NOS DAC builders and negate resorting to the SD-players. Those things have extremely low jitter and ability to be slaved by the DAC clock, but they basically put you back to a 50 CD capacity cdplayer from the 90's in functionality.

The beauty of asych usb is the flexibility to use the computer with 3+TB storage, instant access, VST, foobar, hdcd decoding, etc. But as of yet I haven't seen an asych USB design to where the clock and outputs were isolated on the USB side such that the clock could be powered with a high quality PS with clean ground and could be shared for reclocking right at the DAC which is the ultimate low jitter solution that the SD-players have. Same high quality shunt powered noise free clock driving the DAC inputs and the xmos is the ideal situation a lot of us have been waiting on.

pcourtney 10th August 2011 06:26 PM

x2.

great post Regal, it would be nirvana for a lot of us, hope Lucien can figure out how to help us with something along the lines you mention

3nity 13th August 2011 09:56 AM

I would be interested in this too.
Let me know how it develops.

Thank you.

Lorien 13th August 2011 11:40 AM

Quote:

throw a simple 4 or 7 (multiple grounds) pin 2.54 pinheader to 3-4 x bnc (with or without mclk) adapter pcb, plus perhaps a simple 1 or 2 ubnc to 1-2 fullsize board mount RCA/BNC for coax for output and input connections onto spare space on an existing job. shouldnt cost more than a few dollars each, or depending on your board manufacturer possibly almost free if spare space is utilized.
Yes, I've also thought to these options but I still believe that it's better to minimize the number of connectors/wires in output signal's paths, especially if those signals are I2S word clock & I2S master clock. I saw on the scope what pinheaders could do to a fast clock signal... that's why I've choosed uBNC conns against pinheaders even if the latest ones are simple and common these days.
On the other hand, I could use 2.54mm headers for I2S Data and Bitclock leaving uBNCs for WordClock and MasterClock signals... but the paranoia in me says to leave the pinheaders for DC and low freq. signals only.

@ Alan: You have PM. As I've said earlier, this card have the price of 99 Euro but the shipping costs varies according to destination.

Quote:

It seems Lucian's device has quite low jitter via I2S, as a lot of other users of the BuffII struggled with I2S lock and lowest DPLL bandwidth.
Thank you vanwykca for sharing your experience with WaveIO. I am confident that jitter can be further minimized and I hope future revisions of this card will bring enhancements, mostly to I2S signals. SPDIF is bound to jitter and it's a lost cause for me :Ouch:

Quote:

As far as the galvanic isolation have you considered a manual switch to select a lower USB rate (12 Mbit/s) that would allow galvanic isolation with adum's on the USB side ( but possibly loosing hirez,) It would be a real boon for NOS DAC builders and negate resorting to the SD-players.
Yes I thought about that but there aren't any chances for that switch to exist on the card and that's because XMOS chip is another source of noise thus it must be isolated from the outputs too so, the USB isolation is useless in this scenario. Though, there is another solution for this and I'll implement it in future revisions of WaveIO. For now, I'll stick with I2S output reclocking and adding pinheaders to the non-isolated I2S side. Also there will be uBNC footprints compatible with U.FL and W.FL products as well, thanx to qusp!

Kind regards,
L

Nikon1975 13th August 2011 01:58 PM

Could you send me the price for Japan?

D.


All times are GMT. The time now is 10:28 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 17.65%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio

Wiki