ognam2

Re: Modular multi channel DIY AD/DA Box
« Reply #360 on: April 22, 2010, 03:48:52 AM »
Very interesting Project!
Are there already finishes units? Maybe some Pictures?
Which boards to I need to do A 8x ADAT AD/DA Box, and where can I get them?

Thanx Jonas



rob_gould

Re: Modular multi channel DIY AD/DA Box
« Reply #361 on: April 22, 2010, 04:10:42 AM »
Very interesting Project!
Are there already finishes units? Maybe some Pictures?
Which boards to I need to do A 8x ADAT AD/DA Box, and where can I get them?

Thanx Jonas

I suggest you read the thread from top to bottom.  All your questions are answered and you would do well to get totally up to speed on what's going on here. 

I don't want to be dismissive but it's a complicated project with a lot of potential variables.

rob_gould

Re: Modular multi channel DIY AD/DA Box
« Reply #362 on: April 28, 2010, 06:09:34 AM »
I am slowly working on a way to interface these to the computer via a cheap and simple ethernet cable

Hey baadc0de,

Just wondering if you had made any further progress on this interface?  You seemed to really be going full steam ahead for a while.

Any news?!

Cheers,

Rob  :)

smallbutfine

Re: Modular multi channel DIY AD/DA Box
« Reply #363 on: April 30, 2010, 05:11:46 AM »
Well, Rob, the devil is in the details. Developing such an interfacing is easily a commercial grade project. As far as I know he worked on the ASIO part of a driver and managed to transport raw audio over LAN interface between computers...
Me myself started a KS/WDM pc driver and managed to get a 24bit/96khz configurable dummy driver working up to the interface of a network device driver where i got stuck and hold on to make myself clear about the converters side of things....
"In the past we suffered from crimes, today we suffer from laws."
Tacitus

www.audiomh.de

joe333

Re: Modular multi channel DIY AD/DA Box
« Reply #364 on: May 05, 2010, 02:22:15 AM »
Hi

This thread looks ended!!
Somebody has build the AD/DA with success?
Opinions about how it sounds compared with commercial ones?

thanks

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #365 on: May 05, 2010, 02:40:16 AM »
No it is not ended. :D

Currently we are waiting for the AD chips and then many members of this forum will start to build ADCs I think. The group order of AES output for the ADC is done andthe PCBs are in production. The group buy of the DACs will come next. And I know there are other developments running in the background.

Raphael

rob_gould

Re: Modular multi channel DIY AD/DA Box
« Reply #366 on: May 05, 2010, 04:14:13 AM »
Well, Rob, the devil is in the details. Developing such an interfacing is easily a commercial grade project. As far as I know he worked on the ASIO part of a driver and managed to transport raw audio over LAN interface between computers...
Me myself started a KS/WDM pc driver and managed to get a 24bit/96khz configurable dummy driver working up to the interface of a network device driver where i got stuck and hold on to make myself clear about the converters side of things....

Ah excellent - glad to see this thread getting some updates.

Thanks for your input too s-b-f - I forgot to reply to your reply the other week ;)

Cheers,

Rob

Tubemooley

Re: Modular multi channel DIY AD/DA Box
« Reply #367 on: May 05, 2010, 05:55:44 AM »
I hate to be a snot...... But I already have my PCM4204's. I had them before I had the etch from Raphael. Come on guys.... Let's get with it. As soon as my lithium kicks in, I'll sit down and solder those TQFP-64 bad boys. Oh mama........... DW.

SIXTYNINER

Re: Modular multi channel DIY AD/DA Box
« Reply #368 on: May 05, 2010, 01:14:43 PM »
bump

>>" 1 Picture say what billions words cannot "<< - >>"SMD Kill the DIY STAR"<<
Why in the  forum  if no share

jdbakker

Re: Modular multi channel DIY AD/DA Box
« Reply #369 on: May 05, 2010, 02:55:18 PM »
bump

...why?

The last post to this thread was less than eight hours before yours; the last post by the thread-starter/designer less than eleven.

As far as I can tell this was your first post to this thread. Do you have a specific question which was not yet answered?

JD 'IDGI' B.


mhelin

Re: Modular multi channel DIY AD/DA Box
« Reply #370 on: May 06, 2010, 02:54:43 AM »
Is it OK to use CAT-5e cable for connecting the AD/DA modules using I2S directly to a PCI soundcard (using some transmitter/receiver chips and transformers)? Some folks use the ESI [email protected] soundcard (http://www.thomann.de/gb/esi_juliat.htm ) for connecting DIY DAC's via I2S (which is only meant to be used "inter IC", not directly as interconnect between devices). This soundcard has two boards, the other has the PCI controller (Envy24HT), and the other the converters and is detachable, so you only had to design a digital board (I2S or AES could also be possible) which replaces the analog board. The soundcard is quite an inexpensive one though it also supports chaining of multiple cards, but I'm not sure about it's jitter performance in such case.  Well, another thing is that CAT-5 cable only has twisted pairs so we would have to use two cables for 8 channels in and 2 out. [email protected]'s analog board is only a 2 in 2 out though, not sure if all of the Envy24 HT inputs and outputs are exposed on header (guess not, and the driver doesn't support them either, but VIA general driver might be able to do that).

Easy I2S from [email protected]: http://www.head-fi.org/forum/thread/242285/easy-i2s-from-juli-pci-sound-card

Seems the folks there doesn't much know what they are doing. The signals on scope (some pics posted in the thread) look just awful (lots of ringing and everything else).

« Last Edit: May 07, 2010, 02:50:19 AM by mhelin »
Mikko

Tubemooley

Re: Modular multi channel DIY AD/DA Box
« Reply #371 on: May 06, 2010, 04:28:10 AM »
This is a difficult question. Some people say yes it will work. Others say no it will not work. Looking at SPDIF/AES signals on a scope is borderline nightmare. They're pretty messy. You have to be able to see the good stuff among all the noise and ringing. It's not that easy. AES/EBU is a modified form of RS-422. It is a very specific protocol specified by the AES society. When implemented the way it's spec'd, it works. When implemented another way...... well.... ya' never know. I have read about guys who transmit AES over Cat-5 and it worked for them. Now concerning I2S...... I think you're even further out on a limb doing that. I2S is not designed to go long distances. Maybe inches. Not feet or meters. Sketchy at best. DW.

jdbakker

Re: Modular multi channel DIY AD/DA Box
« Reply #372 on: May 06, 2010, 05:11:56 AM »
Is it OK to use CAT-5e cable for connecting the AD/DA modules using I2S directly to a PCI soundcard

Not enough information.

As Tubemooley indicates, length is an issue. A few inches will probably work fine, an entire 100m-reel probably won't. Adding series termination resistors (as mentioned in the thread you linked to) will help. Signal rise-time is a factor, probably not documented for the [email protected] Grounding/ground loops can get in the way. This approach will likely not be too great from a jitter POV.

On the other hand, CAT-5 is cheap, and you can just try it and see if you like the results. Do add a series resistor in each signal line at the driving ([email protected]) end. Only drive one wire of each twisted pair, connect the other to ground at the [email protected] interface connector. Use the shortest run you can get away with. See if you like it.

(Those scope shots do look ringey, but that may have as much to do with probing technique as with anything else. Properly scoping fast signals is non-trivial).

(using some transmitter/receiver chips and transformers)?

Well, yes, maybe. I was going to write suggestions about using LVDS transmitters/receivers on all of the signals and driving CAT-5 or ribbon cable with them, but at that level of complexity you may as well add a few S/PDIF transmitters on the [email protected] end.

JDB.
[one obvious way to improve jitter performance would be to move the audio clock to the converter end of the cable, as is popular in the CD/DAC-modding crowd. This can get impractical if the clock is synthesized inside the [email protected]'s digital chipset]

joe333

Re: Modular multi channel DIY AD/DA Box
« Reply #373 on: May 06, 2010, 07:37:19 AM »
Dynaudio, Tannoy and tc electronics are not using dig audio over cat5 cable in their surround systems?

jdbakker

Re: Modular multi channel DIY AD/DA Box
« Reply #374 on: May 06, 2010, 08:45:19 AM »
Dynaudio, Tannoy and tc electronics are not using dig audio over cat5 cable in their surround systems?

Apples and oranges.

The question "is there a way to run digital audio over cat5" doesn't necessarily have the same answer as "Is it OK to use CAT-5e cable for connecting the AD/DA modules using I2S directly to a PCI soundcard".

JD 'horses for courses' B.

guitarguy12387

Re: Modular multi channel DIY AD/DA Box
« Reply #375 on: May 06, 2010, 11:38:26 AM »
Hey Guys,

Quick NOOB question, as i've never worked with ADC before.

I want to buy some I2S to ADAT boards. So when wiring these boards, do we tie two of the outputs of the ADC boards in parallel? That is, is there just one main I2S bus that we use? Or will an I2S to ADAT board have multiple inputs for I2S?

Does that make sense? I am asking because i want to know how many I2S to adat boards i need for 4 of these boards (16 channels).

Thanks.

jdbakker

Re: Modular multi channel DIY AD/DA Box
« Reply #376 on: May 06, 2010, 01:32:47 PM »
I want to buy some I2S to ADAT boards. So when wiring these boards, do we tie two of the outputs of the ADC boards in parallel? That is, is there just one main I2S bus that we use? Or will an I2S to ADAT board have multiple inputs for I2S?

Could be implemented either way, but simple boards with the Wavefront chip will likely have multiple I2S inputs.

I am asking because i want to know how many I2S to adat boards i need for 4 of these boards (16 channels).

Depends on the board, and if you want/need support for double/quad speed (96k/192k).

JDB.
[note that the only ADAT boards I've seen so far are Mikkel's OptoRec/OptoGen, and at first glance they dont' support anything other than 44k1/48k without external multiplexing]

baadc0de

Re: Modular multi channel DIY AD/DA Box
« Reply #377 on: May 06, 2010, 01:34:51 PM »
I am slowly working on a way to interface these to the computer via a cheap and simple ethernet cable

Hey baadc0de,

Just wondering if you had made any further progress on this interface?  You seemed to really be going full steam ahead for a while.

Any news?!

Cheers,

Rob  :)

Hi Rob (and everyone else!)

Yes, I've been working on an ASIO driver using libpcap and FPGA sw/hw that would integrate with rkn80's A/Ds and D/As. I've hesitated about maybe opening another thread for this, but since there's not much to write about, I hope it's appropriate to update you all on the current status here:

sw/driver:
-- can transmit/receive audio using raw audio over ethernet between computers. It has its bugs, but as a proof of concept it works well enough (reliably)
-- This isn't using i2s, it's a simple custom protocol, though I might end up buying specs for AES51, AES47 and AES3 and implement those
-- it works only with ASIO hosts for now, and I have a hard time deciding if I want to go WDM/KS/WaveRT or keep it ASIO only. Don't ask about Mac/Linux yet, please, I'd like to make it work on a WinPC

hw/fpga:
-- i haven't decided on a FPGA to use for this project yet and am unsure how exactly to design an interface "card" that would host it. Help would be duly appreciated.
-- I'm looking at http://www.farnell.com/datasheets/33325.pdf currently, the FPGA itself is cheap enough as is this board
-- I'm looking for a gigabit PHY/MAC to go with this FPGA, integrating it might be painful. There's an opencore that I could use for aid, however: http://opencores.org/project,ethernet_tri_mode
-- something like a 300Mhz core might be able to pull off 64 channels at 96k/24-bit

The general theory is for the FPGA interface card to reside in a box together with the D/A, A/D cards and whatever clocking arrangement you would have and provide you with a gigabit ethernet port that you can connect to a switch or directly to a PC. You would configure the driver with a configuration tool (number of channels, sample rates, ethernet port you connected to, MAC address) and then "It Should Work" with your favourite multitrack recording software :)

If I decide to go the WDM/KS route, it would work with regular applications and games, too.

EDIT: about the (short/long)hand future tasks:

-- make sure the FPGA development board is a good enough one to develop and test on, then buy it
-- select a MAC/PHY chip and design/buy eval circuitry that will get FPGA data to the PC
-- verify that the FPGA<->PC roundtrip works via ethernet MAC/PHY
-- work on the FPGA sw to support a fixed, 2ch input board
-- build and test the A/D input board with FPGA hw
-- connect these and verify that 2ch of audio can be extracted from the A/D [milestone]
-- work on the FPGA sw to support output cards (D/A) and multiple inputs/outputs
-- design the real interface card with the FPGA and MAC/PHY on it
-- ... other nice features
« Last Edit: May 06, 2010, 01:39:51 PM by baadc0de »

jdbakker

Re: Modular multi channel DIY AD/DA Box
« Reply #378 on: May 06, 2010, 01:48:33 PM »
-- i haven't decided on a FPGA to use for this project yet and am unsure how exactly to design an interface "card" that would host it. Help would be duly appreciated.

Have any specific questions? I generally use the Xilinx stuff at work, and several of the Digilent eval boards are cheap and powerful enough.

-- I'm looking for a gigabit PHY/MAC to go with this FPGA, integrating it might be painful. There's an opencore that I could use for aid, however: http://opencores.org/project,ethernet_tri_mode

The folks at Ettus Research tried to use that one for their USRP2 software defined radio platform and found it was broken in so many ways that they were forced to abandon it and write their own.

I'd suggest sticking to 100TX, as that is nearly universally compatible and 'light' enough to consider implementation on a fast (ARM) microcontroller instead of (/in addition to) an FPGA. Three dozen channels at 24/96 should be enough for a start, no?

JDB.

rob_gould

Re: Modular multi channel DIY AD/DA Box
« Reply #379 on: May 06, 2010, 03:18:21 PM »

Hi Rob (and everyone else!)

Yes, I've been working on an ASIO driver using libpcap and FPGA sw/hw that would integrate with rkn80's A/Ds and D/As. I've hesitated about maybe opening another thread for this, but since there's not much to write about, I hope it's appropriate to update you all on the current status here:

sw/driver:
-- can transmit/receive audio using raw audio over ethernet between computers. It has its bugs, but as a proof of concept it works well enough (reliably)
-- This isn't using i2s, it's a simple custom protocol, though I might end up buying specs for AES51, AES47 and AES3 and implement those
-- it works only with ASIO hosts for now, and I have a hard time deciding if I want to go WDM/KS/WaveRT or keep it ASIO only. Don't ask about Mac/Linux yet, please, I'd like to make it work on a WinPC

hw/fpga:
-- i haven't decided on a FPGA to use for this project yet and am unsure how exactly to design an interface "card" that would host it. Help would be duly appreciated.
-- I'm looking at http://www.farnell.com/datasheets/33325.pdf currently, the FPGA itself is cheap enough as is this board
-- I'm looking for a gigabit PHY/MAC to go with this FPGA, integrating it might be painful. There's an opencore that I could use for aid, however: http://opencores.org/project,ethernet_tri_mode
-- something like a 300Mhz core might be able to pull off 64 channels at 96k/24-bit

The general theory is for the FPGA interface card to reside in a box together with the D/A, A/D cards and whatever clocking arrangement you would have and provide you with a gigabit ethernet port that you can connect to a switch or directly to a PC. You would configure the driver with a configuration tool (number of channels, sample rates, ethernet port you connected to, MAC address) and then "It Should Work" with your favourite multitrack recording software :)

If I decide to go the WDM/KS route, it would work with regular applications and games, too.

EDIT: about the (short/long)hand future tasks:

-- make sure the FPGA development board is a good enough one to develop and test on, then buy it
-- select a MAC/PHY chip and design/buy eval circuitry that will get FPGA data to the PC
-- verify that the FPGA<->PC roundtrip works via ethernet MAC/PHY
-- work on the FPGA sw to support a fixed, 2ch input board
-- build and test the A/D input board with FPGA hw
-- connect these and verify that 2ch of audio can be extracted from the A/D [milestone]
-- work on the FPGA sw to support output cards (D/A) and multiple inputs/outputs
-- design the real interface card with the FPGA and MAC/PHY on it
-- ... other nice features

Wow

Wow

Wow!

What incredible work. 

I am so excited about this.  What a perfect partner to the boards that Raphael is supplying - true DIY spirit.

I am sorry that I can't offer any technical help - this is so beyond my level


 

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