deuce42

Re: Modular multi channel DIY AD/DA Box
« Reply #500 on: June 01, 2011, 02:03:01 AM »


One critical thing for me however is the audio over Ethernet - I'm delighted to hear you've made some progress with this :)




Yes this could be so much simpler an arrangement for recording remotely - ie just a macbook pro connected via ethernet cable to this AD/DA project. I am really excited to hear how this tangiblises.

Would I be right in saying that if the audio over ethernet concept was used, there would be no need for the aes/ebu or adat interfacing boards at all and the only components of this project would be:

1) Mainboards with world clock on the boards
2) AD and DA modules
3) 15v and 3.3v power supply
4) Whatever audio over ethernet circuit was required
« Last Edit: June 01, 2011, 02:08:04 AM by deuce42 »


Re: Modular multi channel DIY AD/DA Box
« Reply #501 on: June 26, 2011, 06:18:23 PM »
Hey Raph,

First of all, just huuuuge congrats for your progress on this project !! That's what I've been waiting for years.

What I would dream of is to produce a remote controllable API 500 module with a converter and a MIDI in/out directly on the module. So I could do something like 24 preamp or more, remote controlled, directly "traduced" to ADAT.

Do you think it would be feasible to add a MIDI option to your project ? So we could control from anywhere what is doing the converter ?

If what you're saying on the first page is still valid, you would just have to translate SPI or I2C from/to MIDI messages.

Re: Modular multi channel DIY AD/DA Box
« Reply #502 on: July 27, 2011, 12:04:52 PM »
took a couple months off to actually get some projects accomplished  :P, the ethernet pursuit sounds awesome!  i'm clearly in the minority, but i'd give a toe or two for a couple 8-module ├╝berboards.  just out of curiosity, what sample rate are you pursuing?
There's nothing like the right tool for the job.
And -usually- that's what I end up using...
..nothing like the right tool for the job!

deuce42

Re: Modular multi channel DIY AD/DA Box
« Reply #503 on: August 03, 2011, 01:20:45 AM »
I am a bit lost and overwhelmed in TI chip converter data sheets at the moment. Anyone want to shed some light to me on whether the current AD and DA chips for these modules could be substituted for the newer generation ones 4220 or 4222 for AD and 1798's for DA? I am thinking about voltage and current requirements as well. My thoughts are to go ahead and substitute them but am wondering if I a missing something really obvious that would deserve me a slap.

Rochey

Re: Modular multi channel DIY AD/DA Box
« Reply #504 on: August 03, 2011, 01:35:19 AM »
Deuce,

I'm the systems engineer for those parts. (all PCM parts). What do you need to know?

For immediate clarification, they will not be pin to pin compatible.

Cheers

/R
Expat Audio Home: http://www.expataudio.com

deuce42

Re: Modular multi channel DIY AD/DA Box
« Reply #505 on: August 03, 2011, 01:39:56 AM »
Ah yes thanks for that Rochey.  Yes I figured the pin outs were different and would find a way of perhaps modding this via an external small etched PCB for the new chip,  but was trying to determine whether the PCM 4220 and 1798 would otherwise electronically be compatible to fit into Raphael's circuit.  I had this sneaking suspicion that their power requirements were different and may need other circuit surgery that would make substituting them unviable.

Rochey

Re: Modular multi channel DIY AD/DA Box
« Reply #506 on: August 03, 2011, 01:45:17 AM »
well, the max vin/vout may be different, i.e. full scale input or output voltage may be different between converters, forcing you to redo the gain resistors and filter caps in the opamps around the converters.

The PCM422x also requires a 4V analog rail, rather than a standard 5V rail. Clocks and things should be okay, but it's worth checking the ratio between LRCK and MCK... Providing RKN has used 24.576MHz clocks rather than the usual 12.288MHz, you should be okay.

My suggestion is to stick to the current design before jumping ahead. I think you'll find 118dB is an amazing starting point for diy converters.

Cheers

/R
Expat Audio Home: http://www.expataudio.com

deuce42

Re: Modular multi channel DIY AD/DA Box
« Reply #507 on: August 03, 2011, 01:54:24 AM »
Yes the supply rail issue was as I suspect.

Perhaps your post was the slap around the head I need to stop me going further! Thanks!

Rochey

Re: Modular multi channel DIY AD/DA Box
« Reply #508 on: August 03, 2011, 01:56:31 AM »
glad to be of service
Expat Audio Home: http://www.expataudio.com

rob_gould

Re: Modular multi channel DIY AD/DA Box
« Reply #509 on: September 12, 2011, 08:49:08 AM »

Quick question for Rafael or anyone who thinks they can answer it :)

I'm currently populating the DAC.  It's 0902 REV B.

Are C165 and R165 swapped on the prinout you provided for component placement?  It seems strange that all of the other components around each of the four opamps are identically placed, but C165 and R165 don't follow the same pattern.

Also, when adding the components to the rear of the board,  does the prinout show the component placements as though you're looking at the rear of the board, or from the front, 'through' the board? Hope this makes sense...

Cheers

Rob


volker

Re: Modular multi channel DIY AD/DA Box
« Reply #510 on: September 12, 2011, 12:24:00 PM »
Hi Rob,

I don't have the boards in front of me right now, but that should be easy to determine. C165 and R165 are connected on one side, the other side of C165 goes to ground, R165 not. Should be easy to see which is which, or measure with the multimeter.

Concerning the bottom side, it doesn't matter. None of the capacitors are polarized, just solder in any way. But I would say you're looking at the rear side, not through...


Volker

rob_gould

Re: Modular multi channel DIY AD/DA Box
« Reply #511 on: September 12, 2011, 04:01:44 PM »

Hi Volker,

Thanks for that.  Seems like what you say backs up what's printed on the silkscreen.  Just strange that the component placement changes there.

Point 2 took care of itself.  I wasn't confused over the orientation of the components, I just wasn't sure which components went in which position.  All becomes clear when you finish stuffing the boards and have 4 of one type and 8 of another left over though.

Cheers

Rob

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #512 on: November 09, 2011, 11:53:10 AM »
Hello everybody!

It has become quiet around this project the last few weeks. It was my fault. It was a very turbulent summer this year and unfortunately I had no free time left for this project. Sorry for that. But now at the end of the year I've more free time left and I feel that this is the right time to reactivate the project!
First of all, did anybody build a converter? There have been several members who ordered converters together with an AES front end, so they should be able to get something working (even without a mainboard, just by using some flatband ribbon cables).
Anyway, since I got some messages where people asked for an ADAT interface I decided to postpone the mainboard. I have some prototypes here but there are some issues to be solved before they are really helpful. And besides that I'm now owning a new MacBook Pro and I got one of the last Presonus Firestudio LightPipes. I think it is not the badest idea to have an ADAT interface.
I'm not sure anymore wether Mikkel's boards will work because I recognized that the clocking of the wavefront devices is inverted compared to the rest of the AD/DA chip world. Therefore, I now designed my own boards. The first one is an ADAT interface with 4 lightpipe inputs (=32channels @ 48kHz) mirroring the Firestudio configuration. That board is already lying here on my desk while I'm writing this. I'm going to stuff and test it the next few days and will keep you informed. After that ADAT output will follow. As soon as I've finished the ADAT interface I'll return to the delayed parts. That is the roadmap for now. ;)

Raphael

tmuikku

Re: Modular multi channel DIY AD/DA Box
« Reply #513 on: November 09, 2011, 11:57:27 AM »
Jeah! cool  8)

gemini86

Re: Modular multi channel DIY AD/DA Box
« Reply #514 on: November 09, 2011, 12:12:21 PM »
Yay! adat would make this project perfect for me.
- Rodney

"...you better call Kenny Loggins, 'cause you're in the danger zone."

letterbeacon

Re: Modular multi channel DIY AD/DA Box
« Reply #515 on: November 09, 2011, 01:42:08 PM »
Very exciting - looking forward to reading more!

JW

Re: Modular multi channel DIY AD/DA Box
« Reply #516 on: November 09, 2011, 07:35:17 PM »
I gather the line amp is going to be IC opamp based? (I didn't read through all the pages, but I will) It would be awesome to have the option to use a discrete opamp, even transformers ala the burl stuff. Maybe a way to combine one of the API style boards available here if desired? I would go all out for some thing like that.

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #517 on: November 12, 2011, 09:32:05 AM »
JW, I'm not planning to do something with DOAs. All my designs are IC-based. If you want to go for that, you're welcome, but you are on your own then.
anyway here is a pic of the ADATin board I'm going to populate today.

Raphael


gemini86

Re: Modular multi channel DIY AD/DA Box
« Reply #518 on: November 12, 2011, 01:25:34 PM »
Are there boards (ADC and DAC) still available for this somewhere?

This whole time I've been waiting and watching this thread, hoping for ADAT...
- Rodney

"...you better call Kenny Loggins, 'cause you're in the danger zone."

rkn80

Re: Modular multi channel DIY AD/DA Box
« Reply #519 on: November 13, 2011, 10:51:13 AM »
yes I still have ADC and DAC boards left. I think I'll put them on the black market section next few days.

Raphael


 

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