Modular multi channel DIY AD/DA Box

Hi Raphael,

how did the initial clocking board test go? Did you get it working on the first try?

What about the plans for the "motherboards", do you first want to finish the clocking, and then move to that?

Hi,

the clocking boards are working so far.
Regarding the mainboards I expect some prototype PCBs on Wednesday. These prototypes are smaller versions of the big mainboard with the new and final bus layout. The old one turned out to have some disadvantages. To avoid confusion: The change in the bus layout does not affect the modules there is no change needed.

Raphael

Here is a pic of the mainboard prototype boards I'm currently populating.

changed to 1 module per mainboard i see.  might be reading too much between the pixels, but looks like you may have made it possible to daisy chain them in a stack with headers instead of having to wire everything?

No, two modules per mainboard because that reflects most of the orders I got.
But you can daisy chain them with headers, yes you're right.
I'll post more pictures later. That will explain it faster then writing thousand words.

Raphael

rkn80 said:

No, two modules per mainboard because that reflects most of the orders I got.

Click to expand...

there's that "reading between the pixels" getting me in trouble,

rkn80 said:

But you can daisy chain them with headers, yes you're right.

Click to expand...

and there it is making my day.  pin linkage is just about as good as continuous trace in my book, and way more convenient to rack.  well played.

rkn80 said:

I'll post more pictures later. That will explain it faster then writing thousand words.

Click to expand...

indeed it will.  thanks for the pre-update!

There are so many options to configure a unit based the small modules...  :
I think, when the final box is finished I'll use one afternoon to write down all options...

These two boards I'll use for 4 DAC modules giving a 16channel DAC-Unit. Later I'll stuff a third one to go for 24channels...
But first let me prepare the AES input.

Raphael

Here you can see the mounted DAC modules.

A box full with i/o modules....  :

hand-soldered, or did you get out your apron and oven mitts  ?

hand-soldered of course!

Hey Raphael

Out of interest, what circuit is on the motherboard? Power supply as well or will this be external?

Hi,

you need to supply the mainboard with +/- 15V for the analog section (if DAC or ADC modules are used) and +3V3 for the digital section.
From the 15V the board generates the +5V and the +3V3 for the analog section via regulator circuits on the mainboard.
The other features are:
- voltage monitor for reset circuit during power-up
- several pin headers for auxiliary circuits (like XLRs, level meter etc.)
- bus interface if you want to connect several mainboards together in order to build a bigger setup
- D25 connectors for i/o
- several LEDs for status display
- galvanic isolation of analog and digital section, e.g. you use two mainboards to build an 8 channel DAC with AES input and galvanic isolation between the AES input circuit and the DAC stage (recommend). But you can also stack the DAC and the AES input modules on one mainboard to get an 8 channel DAC without galvanic isolation
- the businterface can be configured for both directions for the data lines
- galvanic isolated I2C interface (if you want to control the ADCs/DACs via a microcontroller or for new modules in the future)
- the mainboard does support either I2S or TDM format for the internal digital audio stream

Raphael

Hi Raphael

I was following this thread in the beginning but dropped out a little.

Are there boards available for this project?

Matthew,

yes I still have PCBs for all four modules for sale. Please contact me via PM for the details, like how many you want etc.

Raphael

jdbakker and rkn80, I send a pm to you guys, this post just in case your pm box is full...

rkn80 said:

- the mainboard does support either I2S or TDM format for the internal digital audio stream

Click to expand...

will this all end up mux'ed to single wire?

EDIT: to clarify- will the data of all the chips get multiplexed into a single stream down the line, or remain specific to the separate adc's?

Shameless crosslinking to introduce this new topic about DIY Dante stuff to ADDA board audience  8)
http://www.groupdiy.com/index.php?topic=43478.0

Any name yet for this modular multichannel ADDA project? As I'm on a coffee break and sun is shining I propose a name: Modular Audio from Germany, Digital analog converter = MAGDAC

@grantlack: Well some of the TI chips do support a TDM mode that means 8 channels are multiplexed to one data stream. I wanted to open that door with the mainboard but I do not use it yet.

Anyway I attached a pic with the mainboards for the AES input mounted. Please not the different component population.

To be continued...

Raphael